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M Degan

Publications and source records attributed to M Degan.

At least 37 records · Page 2Linked to original sources
PubMed1998

Differential expression of the RET gene in human acute myeloid leukemia.

The RET proto-oncogene product is a receptor tyrosine kinase representing the signal-transducing molecule of a multi-subunit membrane receptor complex for at least two different types of transforming growth factor (TGF)-beta-related neurotrophic factors. We have previously shown that RET gene expression in acute myeloid leukemia (AML) occurs more frequently in AMLs displaying either a monocytic (FAB M4/M5) or intermediate-mature myeloid phenotype (FAB M2/M3) than in leukemias reflecting an earlier stage of myeloid differentiation (FAB M0/M1). To further verify the association between RET expression and the relative maturation stage of AML cells, we have performed a quantitative estimation of relative abundances of RET transcripts among various FAB subtypes of AMLs. By analyzing 13 AML samples and normal hematopoietic cells through a competitive-quantitative RT-PCR approach, we were able to show that the relative levels of RET-specific mRNAs continuously increase with blast cell maturation in human AML, i.e., the amounts of RET gene-specific transcripts differ among RET-expressing AMLs, being higher in the more differentiated FAB phenotypes. In addition, we provide evidence that the relative amounts of RET transcripts increase upon in vitro and in vivo differentiation of leukemic promyelocytes from FAB M3 AML patients, becoming overall comparable to those found in normal granulocytes. These results indicate that RET expression in human AMLs is maturation-associated, probably mirroring the developmental regulation of this gene during differentiation of normal hematopoietic cells.

Acute Disease↗
PubMed1998

Intralymphocyte free magnesium and plasma triglycerides.

To evaluate the relative effect of hypertension and plasma triglycerides on intralymphocyte magnesium we measured ionized intralymphocyte magnesium (Mg(i)) concentration by means of a fluorimetric method based on the dye Furaptra in 4 groups of subjects: 18 normotensive normotriglyceridemic controls (NTNC), 9 hypertriglyceridemic normotensive patients (HTN), 8 hypertriglyceridemic essential hypertensive patients (HTEH), 17 normotriglyceridemic essential hypertensive patients (NTEH). Hypercholesterolemic, diabetic patients and alcoholics were excluded from the study. Mg(i) was found to be statistically reduced (ANOVA test F=10.41, P=0.0001) in both HTN and HTEH (M+/- SD, HTN: 0.235 +/- 0.01, HTEH: 0.236 +/- 0.01 mmol/l) as compared to both NTNC and NTEH (M +/- SD, NTNC: 0.294 +/- 0.008, NTEH: 0.297 +/- 0.009 mmol/l). A statistically significant negative correlation was found in the population as a whole between Mg(i) and plasma triglycerides (n=52, R= -541, P=0.00004). Our data suggest that hypertriglyceridemia per se and possibly the so-called plurimetabolic syndrome is characterized by low intralymphocyte free magnesium.

Adult↗
PubMed1998

Intralymphocyte free magnesium and calcium and insulin tolerance test in a group of essential hypertensive patients.

In order to assess the links which are claimed to exist between peripheral insulin resistance and intracellular magnesium and calcium concentrations, we measured free intralymphocyte magnesium (Mg(i)) and calcium (Ca(i)) concentrations as well as the rate constant of plasma glucose disappearance (K(itt)) after insulin injection (insulin tolerance test: ITT) in a group of 16 normotensive control subjects (NC) and 34 essential hypertensive subjects (EH). Mg(i) and Ca(i) were measured in triplicate by means of a fluorimetric technique based on the dyes furaptra and fura-2 respectively. K(itt) values proved significantly reduced in EH as compared to NC (M +/- SD, EH: 4.49 +/- 1.31 vs 5.28 +/- 1.19, P <0.05; 95% confidence limits: 0.23-1.5). Mg(i) and Ca(i) were not statistically different in EH as compared to NC subjects (Mg(i), NC: 266 +/- 20 micromol/l; EH: 245 +/- 50 micromol/l; Ca(i), NC: 47 +/- 9 nmol/l EH: 46 +/- 13 nmol/l). We found a statistically significant inverse correlation in the whole study group between K(itt) and body mass index (R= -0.363, P<0.01) and a statistically significant positive correlation between K(itt) and Mg(i) (R=0.347, P=0.013) was found. In a step-up multivariate regression analysis including blood pressure, plasma lipids, BMI, plasma magnesium, fasting insulin, fasting glucose, Mg(i) and Ca(i), the dependent variable K(itt) is statistically significantly correlated with body mass index and Mg(i). In a first attempt to study the relationships between insulin resistance, Mg(i) and Ca(i) in nucleated cells, the chosen index of peripheral resistance seems to be linked to intracellular free magnesium.

Adult↗
PubMed1998

Oxidized low density lipoprotein (LDL) and platelet intracellular calcium: interaction with nitric oxide.

The present study tested the effects of ox-low density lipoprotein (LDL) on nitric oxide (NO)-dependent decrease in agonist-stimulated [Ca2+]i. The effects of ox-LDL on platelet aggregation were also evaluated. Platelets loaded with FURA 2 AM (2 micromol/litre) were incubated with NO-donors for 2-10 min to obtain a 40-50% reduction in \[Ca2+]i and with NO-donors plus ox-LDL (100 microg of protein/ml). Thrombin (0.03 U/ml) was used as an agonist. In some experiments 8-Br-cGMP (0.5-1 mmol/l) was used to investigate the NO-dependent intraplatelet signalling system. Slightly oxidized LDL was obtained by leaving native LDL in the light at room temperature for at least 7 days. Ox-LDL did not cause any increase in thrombin-induced [Ca2+] (control: 215.4 +/- 44.3 nmol/l, ox-LDL 223.4 +/- 35.3 nmol/l, M +/- SEM; n = 8) and platelet aggregation (control: 78.7 +/- 4.9% , ox-LDL: 78.9 +/- 4.2% , n = 12). Ox-LDL antagonized the effects of NO-donors on platelet [Ca2+]i (NO-donor: 137.4 +/- 22.1 nmol/l, NO + ox-LDL: 177.3 +/- 27.6 nmol/l, n = 11; P < 0.001) and platelet aggregation (NO-donor: 15.4 +/- 3.4% , NO + ox-LDL: 28.9 +/- 3.8%, n = 24; P < 0.001). Ox-LDL did not affect the inhibitory activities of 8-Br-cGMP on platelet aggregation (8-Br-cGMP: 22.0 +/- 8.5%, 8-Br-cGMP + ox-LDL: 19.3 +/- 7.8%, n = 5) and platelet [Ca2+]i . In conclusion, slightly oxidized LDL does not directly activate platelets and does not i affect the intracellular NO-dependent signalling system. The present results suggest that LDL reduces the antiplatelet activity of NO mainly by preventing its biological effects.

Journal Article↗
PubMed1998

The F2-isoprostane 8-epiprostaglandin F2alpha increases platelet adhesion and reduces the antiadhesive and antiaggregatory effects of NO.

F2-isoprostanes are prostaglandin (PG) isomers produced in vivo through free radical-catalyzed peroxidation of arachidonic acid, which may affect platelet function. The current study investigated the effects of 8-epiprostaglandin F2alpha (8-epi-PGF2alpha) on critical events of platelet activation. A dose-dependent increase in platelet adhesion to fibrinogen- and plasma-coated microwells by 8-epi-PGF2alpha (1 to 1000 nmol/L) was observed when resting platelets (plasma from 1.3+/-0.2% to 5.5+/-0.2%, EC50 of 48 nmol/L; fibrinogen from 3.3+/-0.3% to 6.4+/-0.2%, EC50 of 35 nmol/L; mean+/-SEM, n=8, P<0.001) and thrombin-stimulated human platelets were used. The expression of the adhesion molecule glycoprotein IIb/IIIa was increased by 10 to 1000 nmol/L 8-epi-PGF2alpha in resting platelets (from 64.8+/-2.1% to 83.9+/-1.3%; n=5, P<0.01) and in stimulated platelets. The secretion of the glycoprotein GMP-140 increased only in the presence of both thrombin and 10 to 1000 nmol/L 8-epi-PGF2alpha (from 48.5+/-3.1% to 63.1+/-2.0%, P<0.05). The antiaggregatory effects of both the NO donor NOR-3 (basal, 21.4+/-4.6%; with 8-epi-PGF2alpha, 30.8+/-6.9%; n=14, P<0.05) and endothelial cells that release NO (basal, 18.5+/-4.6%; with 8-epi-PGF2alpha, 30.7+/-5.3%; n=15, P<0.001) were also reduced. All of these effects were prevented by the thromboxane receptor antagonist GR32191 but not affected by acetylsalicylic acid. An increase in free intracellular calcium concentration, measured with the use of fura 2, was observed with 8-epi-PGF2alpha. In conclusion, F2-isoprostanes may participate in oxidative injury by inducing platelet activation and by reducing the antiplatelet activity of NO: increased platelet adhesiveness and expression of the fibrinogen receptor are induced by nanomolar amounts of 8-epi-PG-F2alpha. Platelet secretion and aggregation can also be induced in the presence of platelet agonists.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1997

Association of Kaposi's sarcoma-associated herpesvirus-positive primary effusion lymphoma with expression of the CD138/syndecan-1 antigen.

Primary effusion lymphoma (PEL) represents a novel B-cell non-Hodgkin's lymphoma (NHL) type associated with Kaposi's sarcoma-associated herpesvirus infection and typically growing as lymphomatous effusions in the body cavities. The precise B-cell subset from which PEL originates as well as the biologic mechanisms responsible for its peculiar growth pattern are unclear. In this study, we have analyzed PEL for the expression status of CD138/syndecan-1, a molecule selectively associated with late stages of B-cell differentiation and implicated in cell-to-cell and cell-to-extracellular matrix interactions. PEL patient samples (n = 7) and cell lines (n = 5) were investigated by multiple approaches, including immunocytochemistry, flow cytometry, RNA analysis, and Western blot studies. For comparison, lymphomatous effusions other than PEL (n = 13) and tissue-based NHL (n = 103) were also tested. Expression of CD138/syndecan-1 associates at high frequency with PEL (5 of 7 patient samples and 5 of 5 cell lines), whereas it is consistently absent among other lymphomatous effusions (n = 13). The CD138/syndecan-1 isoform expressed by PEL has an average molecular weight of 420 kD, which is substantially different from that of CD138/syndecan-1 molecules generally expressed by plasma cells. These data, along with previous immunophenotypic evidence, unequivocally define that PEL cells represent a preterminal stage of B-cell differentiation and may bear implications for the peculiar growth pattern of this lymphoma.

Herpesvirus 8, Human↗
PubMed1997

Reed-Sternberg cells of classical Hodgkin's disease react with the plasma cell-specific monoclonal antibody B-B4 and express human syndecan-1.

Although the cellular origin of Reed-Sternberg (RS) cells of classical Hodgkin's disease (HD) has been a controversial issue for many years, recent immunophenotypic and molecular studies have suggested that RS cells of a subset of classical HD cases may be related to B cells. To further define the immunophenotypic features and the differentiation stage of RS cells, a series of 56 HD samples, including both nodular lymphocyte predominance (LP) (eight cases) and classical HD (nodular sclerosis [NS], 32 cases; mixed cellularity [MC], 16 cases) with a non-T-cell phenotype, were evaluated for the immunohistochemical expression of the B-B4 antigen, a specific marker for terminally differentiated B cells. Because the cDNA of the B-B4 antigen encodes syndecan-1, a member of a family of transmembrane heparan sulfate proteoglycans thought to be involved in binding cells of the B lineage to the interstitial matrix, the B-B4 immunoreactivity was correlated with the expression of syndecan-1 in HD-derived cell lines (L428, KM-H2), as detected by both reverse transcriptase polymerase chain reaction (RT-PCR) studies and Western blotting. Our results show that B-B4 reacts with RS cells and their morphological variants of all cases of classical HD, irrespective of their antigenic phenotype (B, undetermined), albeit at a varying degree of cellular expression. Notably, a high reactivity and staining intensity for the B-B4 monoclonal antibody (MoAb) was restricted to tumor cells from NS HD. In cases of the latter subtype, B-B4 positivity was also found in sclerosis-trapped spindle cells (fibrocytes/fibroblasts). Conversely, the putative tumor cells of nodular LP HD were consistently unreactive with the B-B4 MoAb. Finally, we have demonstrated by RT-PCR, flow cytometry, and Western blotting that cultured RS cells, of B and undetermined phenotype, express syndecan-1 mRNA and produce a form of syndecan-1, recognized by the B-B4 MoAb, which is predominantly associated with glycosaminoglycans and is present at the cell surface. Our detection of the plasma cell-specific antigen B-B4 (syndecan-1) on tumor cells of classical HD further supports that RS cell progenitors may be related to germinal/postgerminal center mature B cells and suggests that expression of syndecan-1 may contribute to some of the typical biologic and histopathologic features of classical HD, with a special regard to the NS subtype.

Antibodies, Monoclonal↗
PubMed1997

Expression of the RET receptor tyrosine kinase and GDNFR-alpha in normal and leukemic human hematopoietic cells and stromal cells of the bone marrow microenvironment.

The RET proto-oncogene product is a receptor tyrosine kinase representing the signal-transducing molecule of a multisubunit surface receptor complex for the glial cell line-derived neurotrophic factor (GDNF), in which a novel glycosyl-phosphatidylinositol (PI)-linked protein (termed GDNFR-alpha) acts as the ligand-binding component. We have analyzed expression of RET and GDNFR-alpha in purified normal hematolymphopoietic cells, leukemia/lymphoma cell lines, and 154 primary samples from patients with hematopoietic malignancies encompassing different lineages and differentiation stages. Relatively low amounts of RET mRNA were found in early CD34+ hematopoietic progenitors, but RET transcripts appeared to increase after myelomonocytic maturation. No expression of RET was found in peripheral blood and tissue B and T lymphocytes. Analysis of human myelomonocytic cell lines was overall consistent with results obtained on purified normal cells. Accordingly, RET expression was mainly confined to acute myeloid leukemias (AMLs) displaying either monocytic (French-American-British M4 and M5) or intermediate-mature myeloid (M2 and M3) phenotypes, being less frequently detected in early myeloid (M0 and M1) AMLs. In contrast, RET mRNA was sporadically detected in B-cell tumors, whereas, among T-cell malignancies, RET transcripts were mainly detected in cells of postthymic and mature T-cell phenotype. RET broad detection in primary tumors was not paralleled by the mutual expression of GDNFR-alpha, which was detected only in 2 isolated primary samples and in 3 leukemia/lymphoma cell lines. However, GDNFR-alpha transcripts, in the absence of RET mRNA, were found in normal bone marrow stromal cells (BMSC), in BM fibroblasts, and in two osteoblast cell lines previously described to support normal hematopoiesis. In the presence of GDNF-receptors derived from BMSC by PI-specific phospholipase C cleavage, GDNF efficiently bound RET-expressing AML blasts and was functionally active by reducing their clonogenic growth and triggering the monocytic maturation of leukemic cells.

Adipose Tissue↗
PubMed1997

CD30 ligand is frequently expressed in human hematopoietic malignancies of myeloid and lymphoid origin.

CD30 ligand (CD30L) is a type-II membrane glycoprotein capable of transducing signals leading to either cell death or proliferation through its specific counterstructure CD30. Although several lines of evidence indicate that CD30L plays a key role as a paracrine- or autocrine-acting surface molecule in the deregulated cytokine cascade of Hodgkin's disease, little is known regarding its distribution and biologic significance in other human hematopoietic malignancies. By analyzing tumor cells from 181 patients with RNA studies and immunostaining by the anti-CD30L monoclonal antibody M80, we were able to show that human hematopoietic malignancies of different lineage and maturation stage display a frequent and broad expression of the ligand. CD30L mRNA and surface protein were detected in 60% of acute myeloid leukemias (AMLs), 54% of B-lineage acute lymphoblastic leukemias (ALLs), and in a consistent fraction (68%) of B-cell lymphoproliferative disorders. In this latter group, hairy cell leukemia and high-grade B-cell non-Hodgkin's lymphoma (B-NHL) expressed a higher surface density of CD30L as compared with B-cell chronic lymphocytic leukemia and low-grade B-NHL. Purified plasmacells from a fraction of multiple myeloma patients also displayed CD30L mRNA and protein. A more restricted expression of CD30L was found in T-cell tumors that was mainly confined to neoplasms with an activated peripheral T-cell phenotype, such as T-cell prolymphocytic leukemia, peripheral T-NHL, and adult T-cell leukemia/lymphoma. In contrast, none of the T-lineage ALLs analyzed expressed the ligand. In AML, a high cellular density of CD30L was detected in French-American-British M3, M4, and M5 phenotypes, which are directly associated with the presence on tumor cells of certain surface structures, including the p55 interleukin-2 receptor alpha-chain, the alpha(M) (CD11b) chain of beta2 integrins, and the intercellular adhesion molecule-1 (CD54). Analysis of normal hematopoietic cells evidenced that, in addition to circulating and tonsil B cells, a fraction of bone marrow myeloid precursors, erythroblasts, and subsets of megakaryocytes also express CD30L. Finally, we have shown that native CD30L expressed on primary leukemic cells is functionally active by triggering both mitogenic and antiproliferative signals on CD30+ target cells. As opposed to CD30L, only 10 of 181 primary tumors expressed CD30 mRNA or protein, rendering therefore unlikely a CD30-CD30L autocrine loop in human hematopoietic neoplasms. Taken together, our data indicate that CD30L is widely expressed from early to late stages of human hematopoiesis and suggest a regulatory role for this molecule in the interactions of normal and malignant hematopoietic cells with CD30+ immune effectors and/or microenvironmental accessory cells.

Acute Disease↗
PubMed1997

The role of eosinophils in the pathobiology of Hodgkin's disease.

BACKGROUND: Even though the presence of a prominent tissue eosinophilia represents a common histopathologic feature of Hodgkin's disease (HD), eosinophils have been mainly regarded as 'innocent' bystanders recruited and activated during the cellular reaction typical of HD. To evaluate the putative role of eosinophils or eosinophil-derived cytokines on tumor-cell regulation in HD, we have analyzed these cells for the functional expression of surface ligands (L) of the tumor necrosis factor (TNF) superfamily, whose specific receptors are known to transduce proliferation signals at the surface of Hodgkin (H) and Reed-Sternberg (RS) cells. MATERIALS AND METHODS: Eosinophils from peripheral blood of healthy donors and patients with HD, primary hypereosinophilic syndrome (HES), or secondary hypereosinophilia (HE), were purified by density gradient centrifugation and immunomagnetic depletion of residual granulocytes. RESULTS: By immunostaining and mRNA analysis, we were able to show that eosinophils from normal donors and patients with HD, HES, and HE express a number of receptors and ligands of the TNF superfamily, including CD40, CD40L, CD30L, CD95/Fas, CD95/FasL and 4-1BB. In addition, we provide evidence that cytokines regulating eosinophil proliferation and activation, i.e., interleukin (IL)-5, IL-3, and granulocyte-macrophage colony-stimulating factor, are able to enhance the cellular density of several TNF superfamily ligands and/or receptors at the surface of cultured eosinophils. Finally, we have shown that native CD40L and CD30L at the surface of purified eosinophils are functionally active and able to transduce proliferative signals on CD40+ and CD30+ target cells, including cultured H-RS cells. CONCLUSIONS: Our data suggest that eosinophils may act as important elements in the pathology of HD by providing cellular ligands for TNF-superfamily receptors (CD40, CD30, CD95/Fas) able to transduce proliferation and antiapoptotic signals at the surface of H-RS cells. The presence on eosinophils of receptors for TNF ligands expressed by activated T cells (i.e., OX40L, FasL, CD40L, 4-1BBL), also suggest that eosinophils may contribute to the deregulated network of interactive signals between H-RS cells, T cells, and other surrounding reactive cells.

Antigens, Neoplasm↗
PubMed1997

[Peripheral insulin resistance and free intralymphocyte magnesium and calcium concentrations in patients with essential hypertension].

To ascertain the claimed links between peripheral insulin resistance and intracellular magnesium and calcium concentrations, we measured free intralymphocyte magnesium (Mg(i)) and calcium (Ca(i)) concentrations, as well as the rate constant of plasma glucose disappearance (K(itt)) after insulin injection (insulin tolerance test: ITT), in a group of 15 normotensive control subjects (NC) and 29 essential hypertensive subjects (EH). Mg(i) and Ca(i) were measured in triplicate by means of a fluorimetric technique based on the dyes furaptra and fura-2 respectively. K(itt) value were significantly reduced in hypertensive subjects as compared to control subjects (M +/- SD, EH: 4.54 +/- 1.31 vs 5.63 +/- 1.07; p < 0.02; 95% confidence limits: 0.22-1.96). Mg(i) and Ca(i) were not statistically different in hypertensive subjects as compared to control subjects (Mg(i), NC: 0.274 +/- 0.02 mmol/L; EH: 0.248 +/- 0.05 mmol/L; Ca(i), NC: 47.6 +/- 9 mmol/L, EH: 46.7 +/- 13.6 mmol/L). A statistically significant inverse correlation was found in the whole study group between K(itt) and body mass index (R = -0.394, p = 0.01) and a statistically significant positive correlation between K(itt) and Mg(i) (R = 0.386; p = 0.012). The latter correlation was no longer statistically significant if adjusted for body mass index. Our data are in favour of a link between index of peripheral insulin resistance and body mass index. A dependence from Mg(i) is possible but the study lack so far the statistical power to demonstrate it.

Blood Glucose↗
PubMed1997

Human granulocyte-macrophage colony-stimulating factor supports the clonogenic growth of B-lineage acute lymphoblastic leukemias expressing myeloid antigens.

The effects of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-3 and IL-6 on clonogenic growth of blast-cell progenitors from 19 immunologically defined CD10-positive B-lineage acute lymphoblastic leukemias (ALL) coexpressing (My+ALLs) or not (My-ALLs) myeloid antigens have been studied. Our results demonstrate that GM-CSF was able to support the clonogenic growth of blast cells from My+ALLs, being totally ineffective on My-All samples. Accordingly, both alpha and beta chains of GM-CSF receptor (R) were expressed by My+ALL blasts, as investigated by reverse-transcriptase polymerase chain reaction (RT-PCR). Colony cells from GM-CSF-stimulated My+ALL cultures displayed the same immunophenotype as primary leukemic cells at diagnosis (CD10+, CD19+, CD22+), and retained the expression of myeloid-associated antigens and of GM-CSF-R transcripts. Moreover, My+ALL blasts showed a preferential sensitivity to the growth-promoting activity of IL-3 and IL-6, as compared with My-ALL cells. In addition to rearrangements of the JH region of immunoglobulin genes, My+ALL cells showed aberrant rearrangements of gamma (three cases) and beta (two cases) T-cell receptor genes, as well as of bcr sequences (three cases). Our data, showing an unexpected cross-lineage response of My+ALLs to GM-CSF, and their preferential stimulation by IL-3 and IL-6, as compared with My-ALLs, further support the concept that My+ALLs represent a separate entity with unique biological features.

Adolescent↗
PubMed1996

Human eosinophils express functional CD30 ligand and stimulate proliferation of a Hodgkin's disease cell line.

The presence of a prominent tissue eosinophilia represents a typical histopathologic hallmark of Hodgkin's disease (HD). To evaluate the putative role of eosinophils on tumor cell regulation in HD, we have analyzed these cells for the functional expression of CD30 ligand (CD30L), a surface molecule able to transduce CD30-mediated proliferation signals on Hodgkin's (H) and Reed-Sternberg (RS) cells. The results demonstrate that circulating and tissue eosinophils from normal donors and patients with HD or hypereosinophilic syndrome (HES), display CD30L mRNA and express CD30L protein, as shown by immunostaining with a specific monoclonal antibody (M80) and with a biotinylated soluble CD30-Fc fusion protein. The surface density of CD30L on eosinophils from HD and HES patients was remarkably higher compared with healthy donors, probably reflecting a cytokine-mediated upregulation in these pathologic conditions. Accordingly, we provide evidence that cytokines regulating eosinophils proliferation and activation, ie, interleukin-5 (IL-5), IL-3, and granulocyte-macrophage colony-stimulating factor (GM-CSF), are able to enhance the cellular density of CD30L on purified eosinophils from normal subjects. Finally, we show that native CD30L on human eosinophils is a functionally active surface structure able to transduce proliferative signals on CD30+ target cells, including cultured H-RS cells. Our data suggest that eosinophils may not merely represent innocent bystanders, but rather act as important elements in the pathology of HD by contributing to the deregulated network of CD30/CD30L-mediated interactive signals between H-RS cells and surrounding reactive cells.

CD30 Ligand↗
PubMed1996

Effect of single and repeated doses of a new nitroderivative of acetylsalicylic acid on platelet TXA2 production in rats.

The effects of a new ASA-nitroderivative compound, NCX 4016 (ASA-NO2), on platelet TXA2 synthesis after single and repeated doses in the rat were investigated. Compared to ASA, cumulative doses of ASA-NO2 showed similar inhibitory effects on platelet TXA2 synthesis and significant increases in nitrite/nitrate plasma concentrations 1 h after the last drug administration: 24 h later nitrite/nitrate plasma levels returned to the control values, while serum TXA2 concentrations did not change. A time-course study after a single dose of ASA-NO2 showed a significant inhibition of platelet TXA2 production also 24 h after drug administration and a significant increase in nitrite/nitrate plasma levels until 10 h.

Animals↗
PubMed1996

Erythrocyte Na(+)-H+ exchanger kinetics and Na(+)-Li+ countertransport activity in essential hypertensive patients.

The authors measured Na(+)-H+ exchanger kinetics together with Na(+)-Li+ countertransport V(max) in the erythrocytes of 21 subjects with essential hypertension and 16 normotensive control subjects. Na(+)-H+ exchange V(max) appeared to be increased in patients with essential hypertension, while the Na(+)-H+ exchanger affinity for intracellular proton sites (K50%) proved to be unchanged and the index of cooperativity among intracellular proton binding sites as measured by Hill's coefficient (Hill's n) decreased as compared with normotensive control subjects. Na(+)-Li+ countertransport V(max) appeared to be higher in patients with essential hypertension than in control subjects. The authors were unable to find any correlations between Na(+)-H+ exchanger kinetic parameters and metabolic variables such as parameters of insulin resistance and plasma lipids. On the basis of the data obtained, erythrocyte Na(+)-H+ exchanger activity was found to be abnormal in two kinetic variables in essential hypertensive patients and showed no simple linear correlations with the main variables of glucose metabolism, plasma lipids, renin or aldosterone.

Adult↗
PubMed1996

In vitro study of the anti-aggregating activity of two nitroderivatives of acetylsalicylic acid.

The antiplatelet activity of two new nitrocompounds, chemically related to acetylsalicylic acid (NCX 4215 and NCX 4016), was studied in vitro to verify the hypothetical dual action of these drugs. Both drugs, in a dose-dependent way, inhibited arachidonic acid-induced platelet aggregation and thromboxane A2 production, measured as thromboxane B2 concentration in whole blood. These effects are likely to be related to cyclo-oxygenase inhibition. NCX 4215 and NCX 4016 in a dose-dependent way inhibited also thrombin-induced aggregation of platelets pretreated with acetylsalicylic acid. These inhibitory effects are related to nitric oxide release and cGMP increase and significantly reversed by oxyhaemoglobin and methylene blue. Either as a cyclo-oxygenase inhibitor or as a nitric oxide donor, NCX 4016 proved to be significantly more potent than NCX 4215.

Arachidonic Acid↗