PubMed Health⌕ Search

Biomedical subjects

J Aznar

Publications and source records attributed to J Aznar.

At least 19 recordsLinked to original sources
PubMed1992

Activated protein C: alpha 1-antitrypsin (APC: alpha 1 AT) complex as a marker for in vitro diagnosis of prethrombotic states.

The purpose of the study was to test whether APC: alpha 1AT complex is a useful clinical marker of the activation of coagulation. The rationale for this is that activated protein C may appear in circulation at an early stage of blood coagulation, when subcoagulant amounts of thrombin are formed. Given the relatively higher half-life of APC: alpha 1AT as compared to that of thrombin:AT-III (TAT) complexes, we hypothesized that APC:alpha 1AT could represent an amplification of the thrombin generated in the first events of coagulation. Using sandwich ELISA's we measured APC: alpha 1AT and TAT complexes as well as complexes of AT-III with its target proteases in normal subjects and in several clinical groups of patients prone to thrombotic episodes, including pregnancy, preeclampsia, hemodialysis, gynecological tumors, diabetes and oral contraceptives. APC: alpha 1AT complex was significantly increased in all clinical groups as compared to normal subjects and showed relatively higher increases than did TAT and ATM complexes in the majority of the groups studied. There was a significant and positive correlation between APC: alpha 1AT and TAT complex levels in the majority of the groups, as well as between TAT and ATM and between APC: alpha 1AT and ATM complex levels. We conclude that APC: alpha 1AT complex can be used as a sensitive marker of prethrombotic states.

Antithrombin III↗
PubMed1992

Euglobulin clot lysis induced by tissue-type plasminogen activator is reduced in subjects with increased levels of lipoprotein (a).

Several reports have evaluated the in vitro effect of lipoprotein(a) [Lp(a)] levels on the fibrinolytic system, suggesting that high Lp(a) levels may inhibit fibrinolysis by competing for plasminogen binding in different systems. We have studied plasminogen activation induced by tissue-type plasminogen activator (t-PA), as well as other fibrinolytic parameters, in 25 subjects with Lp(a) levels greater than 30 mg/dl and the results were compared with those found in 23 subjects with Lp(a) less than 30 mg/dl. Both groups were similar in age, sex distribution, living habits and lipid pattern. Plasminogen activation, when measured by t-PA-induced euglobulin clot lysis, was significantly decreased in the group with elevated Lp(a) levels (lysis time, 16.7 +/- 3.3 min) compared with the group with low Lp(a) levels (11.8 +/- 2.0 min), although 8 of the 25 subjects with high Lp(a) levels showed plasminogen activation within the range of the control group. A positive significant correlation between Lp(a) levels and t-PA-induced euglobulin clot lysis time was found. No statistical differences were demonstrated between groups for the other fibrinolytic parameters studied. Addition of purified Lp(a) to the euglobulin fraction or to plasma resulted in a decrease in euglobulin clot lysis. The present study shows that t-PA induced plasminogen activation is decreased in individuals with high circulating levels of Lp(a) supporting the hypothesis that Lp(a) may interfere with the physiological functions of plasminogen.

Adult↗
PubMed1992

Hemorheological alterations in mild essential hypertension.

Blood rheological properties were studied in 21 patients suffering from essential hypertension (EHT), degree I-II according to WHO criteria. These patients were diagnosed "de novo". The whole blood filterability (WBF), blood viscosity (BV) at 230 s-1 and 23 s-1, red cell deformability (FI), erythrocyte aggregation in autologous (MEA) and normal plasma (MEAc), fibrinogen (Fbg) and hematocrit (Ht) have been evaluated. In the hypertensive patients we have found decreased WBF, greater BV and FI in comparison with the control group (p less than 0.001). Likewise, MEA and Fbg were increased, though the differences were less significant (p less than 0.01). The evaluation of Ht did not show any differences between the two groups. The results suggest that in the newly diagnosed EHT, clear hemorheological alterations occur, both in plasma and in the erythrocytes, which could play a role in the pathogenesis of the aforementioned disease.

Adult↗
PubMed1992

[Evaluation of 5 methods for the diagnosis of infections by respiratory syncytial virus].

BACKGROUND: To compare and evaluate four different rapid methods of respiratory syncytial virus antigen detection with the isolation of the virus in cell culture. METHOD: Ninety-eight nasopharyngeal swabs were studied, for respiratory syncytial virus isolation in Hep-2 cell line and for RSV antigen detection using direct immunofluorescence and three ELISA methods: Abbot RSV EIA (ELISA-1), RSV Antigen Detection System (ELISA-2) and Directigen RSV (Directigen). RESULTS: Of all 98 samples studied using the five mentioned methods, 42 (43%) were positive for respiratory syncytial virus. The most sensitive methods were ELISA-1 (82%) and immunofluorescence (82%). The most specific ones were direct immunofluorescence (86%) and Directigen (84%). The higher percentage of concordant positive results with respiratory syncytial virus culture were direct immunofluorescence (84%) and Directigen (82%). CONCLUSIONS: Rapid diagnostic methods for respiratory syncytial virus infection can not substitute the isolation method using cell line culture. We believe that respiratory syncytial virus isolation in cell culture combined direct with direct immunofluorescence or Directigen methods are the first choice diagnostic techniques for achieve a higher number of positive results in respiratory syncytial virus infected patients.

Antigens, Viral↗
PubMed1991

Functionally active protein C inhibitor/plasminogen activator inhibitor-3 (PCI/PAI-3) is secreted in seminal vesicles, occurs at high concentrations in human seminal plasma and complexes with prostate-specific antigen.

Protein C inhibitor (PCI) is a heparin-dependent serpin present in a native form in plasma at concentrations of 5 micrograms/mL. In vitro, PCI inhibits activated protein C (APC), thrombin, plasma kallikrein (KK) and urokinase-(uPA) and tissue-type plasminogen activator (tPA), and we have shown in vivo inhibition of APC, uPA and KK by PCI. In order to further characterize the physiological role of PCI, we have measured the level of PCI in several biological fluids. PCI antigen was assayed by ELISA and PCI activity was measured by its capability to form complexes with APC in the presence of heparin. Seminal plasma from voluntary donors had PCI levels (160 +/- 20 micrograms/mL, mean +/- SD) about 30 or 40 times higher than those found in blood plasma. Patients under a fertilization program had significantly reduced PCI seminal levels (110 +/- 35 micrograms/mL). Seminal plasma PCI retained about 45% of its activity immediately after ejaculation, and the activity rapidly decreased following incubation of seminal plasma at 37 degrees C, in parallel with the appearance of complexes of PCI with prostate-specific antigen (PSA). PCI was present in seminal vesicle secretion, obtained by autopsy, at concentration similar to that observed in semen, was mostly active and was not inactivated by incubation of secretion at 37 degrees C. The mean functional and antigen levels of PCI in urine from normal donors were 0.58 and 0.25 micrograms/mL, respectively, whereas in saliva these levels were 20 and 0.8 ng/mL, respectively. Amniotic fluid contained PCI antigen levels of 2.1 +/- 0.2 microgram/mL. These results show that PCI is secreted in the seminal vesicles in a functional form, and suggest that PSA, a major secretory component of the prostate, is responsible for its inactivation. They also suggest a physiological role of PCI in reproduction, and show that PCI is present in various biological fluids.

Amniotic Fluid↗
PubMed1991

Evidence of activation of the protein C pathway during acute vascular damage induced by Mediterranean spotted fever.

Mediterranean spotted fever (MSF) is a rickettsiosis that induces widespread microvascular injury. To obtain quantitative information on the in vivo activation and inactivation of the protein C system during the acute phase of endothelial damage, several components of the protein C pathway were studied in 28 MSF patients. Upon admission (day 1), patients showed clear evidence of endothelial damage as reflected by the significant decrease in the ratio VIII:C/vWF:Ag (0.36 +/- 0.14, mean +/- SD) compared with normals (0.98 +/- 0.14), and clinical and laboratory signs of hemostatic alterations such as decreased platelet count, positive fibrinogen/fibrin degradation products, and increased thrombin:antithrombin-III complex levels. Antigenic protein C (72% +/- 18%) and protein C inhibitor (PCI) (41% +/- 20%) were significantly decreased (P less than .001). Complexes of activated protein C (APC) with PCI or with alpha 1-antitrypsin (alpha 1AT) and of plasma kallikrein with PCI (KK:PCI) were measured using sandwich enzyme-linked immunosorbent assays. APC:alpha 1AT complex levels were increased in patients at day 1 (27 +/- 13 ng/mL) compared with controls (7 +/- 2 ng/mL), and APC:PCI and KK:PCI complexes, which were not detectable in any of the controls, were present in 57% and 75% of the 28 MSF patients, with mean levels of 11 +/- 5 and 46 +/- 16 ng/mL, respectively. After remission of the disease (day 30), a trend toward normal values in the majority of the parameters studied was found. This study shows that, in the course of endothelial injury, MSF patients experience a generalized activation of the protein C pathway, resulting in consumption of protein C and PCI, and in the appearance of APC:inhibitor complexes. Moreover, these data provide the evidence that KK:PCI circulating complexes occur in vivo.

Adult↗
PubMed1991

Erythrocytes metabolically enhance collagen-induced platelet responsiveness via increased thromboxane production, adenosine diphosphate release, and recruitment.

Erythrocytes promoted platelet reactivity in a plasma medium, as demonstrated in an in vitro system that independently evaluated the biochemistry of platelet activation and recruitment. The prothrombotic erythrocyte effects were metabolically regulated, as evidenced by lack of activity of ATP-depleted or glutaraldehyde-fixed erythrocytes. They occurred in the absence of cell lysis as verified by lactate dehydrogenase assays, and had an absolute requirement for platelet activation. The presence of erythrocytes induced a twofold increase in platelet thromboxane B2 (TXB2) synthesis upon collagen stimulation, indicating that erythrocytes modulated platelet eicosanoid formation. Cell-free releasates from stimulated platelet-erythrocyte suspensions, which exhibited increased recruiting capacity, contained 6.9-fold more ADP and 4.9-fold more ATP than releasates from stimulated platelets alone. Following aspirin ingestion, TXB2 formation was blocked, but erythrocyte promotion of platelet reactivity persisted at those doses of collagen that reinduced platelet activation. Moreover, when platelet mixtures consisted of as little as 10% obtained before aspirin plus 90% obtained post-aspirin ingestion, significant erythrocyte enhancement of platelet reactivity occurred, even at low agonist concentrations. These erythrocyte effects would decrease the therapeutic potential of inhibition of platelet cyclooxygenase by aspirin. The erythrocyte-induced modulation of platelet biochemistry and function emphasizes the importance of cell-cell interactions in stimulus-response coupling.

Adenosine Diphosphate↗
PubMed1991

Determination of total, free and complexed protein S in plasma by ELISA, and comparison with a standard electroimmunoassay.

An enzyme-linked immunosorbent assay (ELISA) for measuring total, free and complexed protein S in plasma was developed. To assay free protein S, C4b-binding protein-bound protein S (C4b-BP-PS) was extracted by addition of polyethyleneglycol (PEG) 6000 (5%, final concentration) to plasma samples. Microtiter plates were coated with rabbit anti-human protein S, and bound protein S was detected with labelled anti-protein S antibody. Diluted plasma samples were incubated in the plates overnight at 22 degrees C to permit C4b-BP-PS complexes to dissociate. Mean variation coefficients of 2.1 and 3.2% (intra-assay) and 4.3 and 7.9% (inter-assay) were found for total and free protein S assays, respectively. The ELISA measures free and complexed protein S with equal efficiency as is demonstrated by the fact that the sum of free protein S and C4b-BP-PS complex levels in normal individuals, women in their third trimester of gestation and patients with acute deep vein thrombosis (DVT), equaled the level of total protein S present in the corresponding plasma. Total protein S values obtained with the ELISA, in all groups studied, correlated well with those obtained with a standard electroimmunoassay (EIA) (r = 0.93; n = 40). However, total protein S levels measured by EIA were lower than those assayed by ELISA in pregnant women and in DVT patients. Furthermore, addition of several amounts of purified C4b-BP to NHP, which reduced the recovery of free protein S, did not influence the total protein S values measured by ELISA but slightly decreased the recovery of total protein S measured by EIA. These results indicate the necessity of using assays which accurately and reliably measure the total amount of protein S antigen. After addition of C4b-BP to NHP, the residual functional protein S level was lower than the residual level of free protein S antigen; this lends support to the idea that C4b-BP-PS complex inhibits the activated protein C cofactor activity of protein S.

Carrier Proteins↗
PubMed1991

Interaction of plasma kallikrein with protein C inhibitor in purified mixtures and in plasma.

The interaction between plasma kallikrein (KK) and protein C inhibitor (PCI) and the influence of KK on the complex formation between activated protein C (APC) and PCI was studied in purified systems as well as in plasma in order to assess the significance of these reactions in the plasma milieu. PCI complexed to KK (KK:PCI) or to APC (APC:PCI) was measured by sandwich ELISA's using antibodies directed against each protein in the complexes. The formation of KK:PCI complexes assayed by this method paralleled the inhibition of KK amidolytic activity by PCI in purified system. Incubation of normal plasma (NHP) at 4 degrees C, which can induce prekallikrein activation due to cold activation, resulted in PCI inactivation and appearance of KK:PCI complexes. PCI activity fell to 35% of the NHP and 1.2 micrograms/ml of KK:PCI complex was formed. However, incubation of NHP at room temperature or of prekallikrein deficient plasma at 4 degrees C did not result in significant decrease of PCI activity. Thus the PCI inactivation was associated with prekallikrein activation and complexation to PCI following cold activation. Incubation of exogenous purified KK with NHP resulted in PCI inactivation and complexation with KK in a temperature-dependent manner. Addition of 2.8 micrograms/ml KK to plasma at 4 degrees C resulted in the inactivation of 55% of plasma PCI and the formation of 0.9 microgram/ml KK:PCI which represents 21% of the KK added, whereas at 37 degrees C PCI was inactivated to 30% and only 0.30 microgram/ml KK:PCI complexes were measured. These results indicate that PCI is a major KK inhibitor at 4 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1991

Fibrinolytic parameters in normotensive pregnancy with intrauterine fetal growth retardation and in severe preeclampsia.

In pregnancy a decrease in fibrinolytic activity, which is due to an increase in plasminogen activator inhibitor activity and plasminogen activator inhibitor type 1 and type 2, has been described. Because the placenta is a source of both type 1 and type 2 plasminogen activator inhibitor, we have studied them and other fibrinolytic parameters in a group of normotensive pregnant women with intrauterine fetal growth retardation and in two groups of women with preeclampsia, with or without intrauterine growth retardation. A significant increase in plasminogen activator inhibitor type 1 antigen and plasminogen activator inhibitor activity was observed in preeclampsia, with or without intrauterine growth retardation, but not in normotensive pregnancy with intrauterine growth retardation, when compared with normal pregnancy. Plasminogen activator inhibitor type 2 antigen levels showed a significant decrease in both groups of pregnant women (normotensive or preeclamptic) with intrauterine growth retardation when compared with pregnancies without intrauterine growth retardation. A significant correlation between plasminogen activator inhibitor type 2 levels and fetal weight has been observed in the clinical groups.

Adult↗
PubMed1991

Complexes of activated protein C with alpha 1-antitrypsin in normal pregnancy and in severe preeclampsia.

Protein C is a vitamin K-dependent regulator of blood coagulation. Activated protein C is regulated in plasma in large part by two inhibitors, protein C inhibitor and alpha 1-antitrypsin. Complexes of activated protein C with both inhibitors in plasma samples from subjects with normal or pathologic pregnancy were measured. In normal pregnancy we observed a progressive and significant increase in activated protein C/alpha 1-antitrypsin complex levels, from 9 +/- 3 ng/ml in the first trimester to 16 +/- 3 ng/ml in the third trimester, as well as an increase in alpha 1-antitrypsin plasma levels. In severe preeclampsia, but not in chronic hypertension with superimposed severe preeclampsia, there was a greater increase in activated protein C/alpha 1-antitrypsin levels (25 +/- 10 ng/ml) (p less than 0.001) and a decrease in protein C and protein C inhibitor levels as compared with normal pregnant women at similar gestational ages. These data show an increase in the activation of the protein C pathway in both normal and pathologic pregnancy and provide evidence for an enhancement of thrombin generation in severe preeclampsia compared with chronic hypertension with superimposed severe preeclampsia.

Adolescent↗
PubMed1991

Sexually transmitted diseases in homosexual males in Seville, Spain.

BACKGROUND AND METHODS: The absence of any official statistics on the prevalence of STD in homosexual men in Spain induced us to carry out a prospective study of new homosexual patients who consulted the STD Clinic of the School of Medicine in Seville, between January 1988 and December 1989. The aim of the study was to determine the prevalence of symptomatic and asymptomatic infections in this group of patients. RESULTS: 1805 patients were seen during the study period; 318 patients were homosexual of whom 309 agreed to participate in the study. Of the 309 homosexual men, 108 (35%) had symptoms and the remaining 201 (65%) were asymptomatic. In the symptomatic group the diagnoses were: syphilis 28 (25.9%); urethritis 40 (37%) (of these 40, 11 had Neisseria gonorrhoeae, five had Chlamydia trachomatis, five had Ureaplasma urealyticum, one had Herpes simplex virus and in 18 no pathogen was detected); genital herpes seven (6.4%). Eleven (10%) had concomitant infections. The following infections were found in the asymptomatic group: syphilis 23 (11.4%), N gonorrhoeae six (3%), C trachomatis two (1%), Herpes simplex virus one (0.5%). Antibodies against HIV were detected in 30 (9.6%) of the total group. CONCLUSIONS: Sexually transmitted diseases are common amongst homosexual men in Seville and many of these are asymptomatic.

Adult↗
PubMed1991

Enhancement of platelet reactivity and modulation of eicosanoid production by intact erythrocytes. A new approach to platelet activation and recruitment.

Erythrocytes are known to influence hemostasis. Bleeding times are prolonged in anemia and corrected by normalizing the hematocrit. We now demonstrate that intact erythrocytes modulate biochemical and functional responsiveness of activated platelets. A two-stage procedure, permitting studies of cell-cell interactions and independently evaluating platelet activation and recruitment within 1 min of stimulation, was developed. Erythrocytes increased platelet serotonin release despite aspirin treatment, enzymatic adenosine diphosphate removal, protease inhibition, or combinations thereof. The data suggested that erythrocyte enhancement of platelet reactivity can reduce the therapeutic effectiveness of aspirin. Erythrocytes metabolically modified platelet arachidonate or eicosapentaenoate release and eicosanoid formation. They promoted significant increases in cyclooxygenase and lipoxygenase metabolites upon platelet stimulation with collagen or thrombin. However, with ionophore, erythrocytes strongly reduced platelet lipoxygenation. These erythrocyte modulatory effects were stimulus-specific. Activated platelet-erythrocyte mixtures, with or without aspirin, promoted 3-10-fold increases in extracellular free fatty acid, which would be available for transcellular metabolism. Erythrocyte-induced increases in free eicosapentaenoate may contribute to antithrombotic and anti-inflammatory effects of this fish oil derivative. These results provide biochemical insight into erythrocyte contributions to thrombosis and hemostasis, and support the concept of thrombus formation as a multicellular event.

Adenosine Diphosphate↗
PubMed1991

[Evaluation of the Mycoscreen technique for the detection and quantification of genital mycoplasmas].

A total of 161 samples from genital sources were evaluated using two different methods for genital Mycoplasma isolation: inoculation to urea broth, arginine broth and A7 solid media (standard method) and a new enzymatic method (Mycoscreen Oxoid). The isolation rates for Ureaplasma urealitycum were 42% (standard method) and 49% (Mycoscreen) (sensitivity: 100%; specificity: 88%). The isolation rates for Mycoplasma hominis were 13% (standard method) and 14% (Mycoscreen) (sensitivity: 80%; specificity: 95%). Using the enzymatic method, manufacturer's positive result is defined as a count greater than 10,000 UCC-ml at 24 hours. When we compare the 24 hours results, the concordance rates was 84% (Ureaplasma urealyticum) and 62% (Mycoplasma hominis). Mycoscreen method is a valid and fast technique for the isolation and identification of genital Mycoplasma. It also allows a fast screening of pathologic counts of Ureaplasma urealyticum in genital exudates.

Bacteriological Techniques↗
PubMed1990

Plasminogen activator inhibitors type 1 and type 2 and plasminogen activators in amniotic fluid during pregnancy.

Plasminogen activator inhibitor activity (PAI), PAI-1 and PAI-2 antigen, and other fibrinolytic parameters were evaluated in amniotic fluid during normal pregnancy and compared with that obtained in plasma of pregnant women. The results indicate the presence of both PAI-1 and PAI-2 in amniotic fluid during normal pregnancy. In amniotic fluid, PAI-1 antigen levels increased from 194 +/- 109 ng/ml (first trimester) to 640 +/- 396 ng/ml (third trimester) and PAI-2 antigen levels increased from 72 +/- 57 ng/ml to 173 +/- 97 ng/ml. In contrast, a decrease in tissue-type plasminogen activator (t-PA) antigen level was observed during pregnancy. The PAI-1 levels in amniotic fluid were significantly higher than the PAI-1 levels in plasma of women at a similar gestational age. However, PAI activity, measured using single chain t-PA, was lower in amniotic fluid than in plasma of normal pregnant women. The PAI activity/PAI-1 antigen ratio in amniotic fluid after activation by a denaturing agent increased from 0.003 +/- 0.004 to 0.059 +/- 0.018. These results indicate that high levels of PAI-1 are present in amniotic fluid and suggest that this PAI-1 is present in a latent form that can be reactivated, at least partially, by a denaturing agent.

Amniotic Fluid↗
PubMed1990

Contribution of platelets to increased plasminogen activator inhibitor type 1 in severe preeclampsia.

Plasminogen activator inhibitor activity and antigen were evaluated in plasma, serum and platelet lysate in patients with severe preeclampsia (n = 12), and in normal pregnant women (n = 21). Other parameters, including beta-thromboglobulin and platelet count, were also evaluated. A significant increase (p less than 0.05) in beta-thromboglobulin was observed in platelet poor plasma of preeclamptic women when compared with that of normal pregnant women, and the platelet count was lower in the preeclamptic group than in the normal pregnant group. A significant increase in plasminogen activator inhibitor activity and antigen was observed in platelet poor plasma of the preeclamptic group as compared with normal pregnant women, whereas platelet lysate from preeclamptic women showed a significant decrease in both plasminogen activator inhibitor activity and antigen as compared with that of normal pregnant women. No correlation between beta-thromboglobulin and plasminogen activator inhibitor type 1 antigen in platelet poor plasma was observed, but a significant inverse correlation (r = -0.78, p less than 0.05) between beta-thromboglobulin in platelet poor plasma and plasminogen activator inhibitor-1 antigen in platelet lysate was obtained in preeclamptic patients. However, in platelet poor plasmas obtained from normal platelet rich plasmas activated with thrombin (0.1 IU/ml, 37 degrees C, 1 min), an increase of about 300 ng/ml in beta-thromboglobulin was observed while the increase in plasminogen activator inhibitor was only 4 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗