Modulation of synaptosomal plasma membrane-bound enzyme activity through the perturbation of plasma membrane lipid structure by bupivacaine

We investigated modulations of lipid dynamics and lipid-protein interactions of rat brain synaptosomal plasma membrane (SPM) as one of the possible mechanisms by which the local anesthetic bupivacaine (BPV) has an adverse effect on nerve cell function, with SPM-bound enzyme activity used as a functional probe. The kinetics of BPV impact on the activity of the endoenzymes Ca2+/Mg2+-stimulated ATPase and Na+/K+-stimulated ATPase and the active concentrations of the drug were relevant to those that produce biphasic systemic toxicity. Arrhenius plots of these enzymes showed a transition temperature of 26.6 +/- 1.8 degrees C and 24.5 +/- 1.2 degrees C (mean +/- SD), respectively, in control SPM, which shifted to 17.1 +/- 0.95 degrees C (P < 0.01) and 18.2 +/- 0.85 degrees C (P < 0.05) in SPM treated with 10(-5) M BPV. The Hill coefficients for the allosteric inhibition of Ca2+/Mg2+-stimulated ATPase by Na+ and Na+/K+-stimulated ATPase by fluoride decreased from 1.73 +/- 0.20 and 1.95 +/- 0.25, respectively, in controls to 0.92 +/- 0.09 (P < 0.001) and 1.09 +/- 0.11 (P < 0.001) in the presence of 10(-5) M BPV. The fluidity perturbation in the microenvironment of the ectoenzyme acetylcholinesterase was observed only at 5 X 10(-3) M BPV, as confirmed by the disparity in transition temperature between the controls (22.3 +/- 1.2 degrees C) and the BPV-treated SPM (17.5 +/- 0.8 degrees C, P < 0.01) and that in the Hill coefficient in the two groups: 2.15 +/- 0.24 and 0.97 +/- 0.12 (P < 0.001), respectively. Implications: We propose that under physiological conditions, the neutral and protonated forms of local anesthetics can affect nerve cell function through the asymmetric perturbation of the membrane lipid structure, accompanied by synaptosomal plasma membrane-bound enzyme dysfunction

Plasma tetranectin levels in patients with unstable and stable angina

It has been recently suggested that the acute exacerbation of chronic inflammatory process accompanied by excessive atheromatous plaque-matrix breakdown may be the crucial link between chronic and acute coronary artery disease (CAD). In the light of this probability, the fibrinolytic regulator, tetranectin (TN) was assessed in the plasma of 43 unstable angina (UA) patients, 35 stable angina (SA) patients, and 34 healthy subjects (HS) in association with selected inflammatory and fibrinolytic markers. Plasma TN levels in patients with UA and SA were significantly lower than those in HS (8.18 (7.08-9.58) mg/L and 10.00 (7.22-10.96) mg/L vs 12.09 (11.78-12.37) mg/L, Er < 10(-4)). The sensitivity, specificity and predictive value were 72.1, 97.1 and 97% respectively for UA patients, and 46, 97 and 94% respectively for SA patients. In the 26 (60.5%) of UA patients, which had a complicated in-hospital course, TN levels were significantly lower than those in the 17 (39.5%) uncomplicated UA patients (7.38 (6.77-8.15) mg/L vs 9.67 (8.47-10.84) mg/L, p < 10(-4)). In SA patients the increased levels of C-reactive protein (CRP), fibrinogen (FG), tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-I) and D-dimer (DD), in conjunction with the significant positive correlation between CRP and FG, and of both with DD, revealed the existence of a low-grade inflammatory process accompanied by the subclinical activation of reactive fibrinolysis. The substantial increase in the above-mentioned inflammatory and haemostatic markers, along with the significant correlation between the inflammatory markers and DD, as well as between t-PA and DD or FG in UA patients, was consistent with the acceleration of inflammatory and coagulative/fibrinolytic processes. The negative correlation of TN with CRP (r(s) = -0.707, p < 10(-3)) and FG (r(s) = -0.664, p < 10(-4)) in UA patients and, to a lesser degree, in SA patients (r(s) = -0.563, p < 10(-3) and r(s) = -0.457; p = 0.006 respectively) makes possible the involvement of inflammatory components in the regulation of TN in CAD. The negative correlation of TN with DD in SA (r(s) = -0.356, p = 0.036) and UA (r(s) = -0.319, p = 0.037) patients along with its superior performance characteristics and predictive correlation with UA clinical outcome in comparison with other inflammatory and fibrinolytic variables studied, suggested its possible implication in the pathophysiologically-important processes associated with atheromatous plaque-matrix breakdown and thrombus dissolution. The significant inverse relation between TN and lipoprotein (a) [Lp(a)] observed in SA (r(s) = -0.552, p = 0.001) hinted at the common implication of these fibrinolytic regulators in the pathophysiology of chronic CAD. A further investigation of the role played by TN in CAD could perhaps shed light on its significance as a marker of the development of coronary atheromatous lesions and thrombosis

Imbalance of tissue-type plasminogen activator (t-PA) and its specific inhibitor (PAI-1) in patients with rheumatoid arthritis associated with disease activity

The relationship between plasma fibrinogen, D-dimer (DD), t-PA and PAI-1 and their correlation with disease activity (DA) were studied in 45 patients with rheumatoid arthritis (RA) (group B) to further understand the implication of fibrinolysis in the pathophysiology of RA, The control group constituted 24 healthy subjects (group A). A Stoke index (SI) of DA was assigned to each patient, Patients were divided into two groups: C, minimal-mild DA (SI 1-7); D, moderate-severe DA (SI 8-17), Fibrinogen was elevated in RA correlating positively with SI and CRP, Hypercoagulability counteracted by reactive fibrinolysis was inferred from a 10-fold increase of DD in group B as compared to group A. The relatively lower levels of DD in group D compared to group C and their negative correlation with SI (r(s)=-0.49, p=0.0006) indicate the tendency of fibrinolysis to decrease with the increase of DA. Significant elevation of t-PA and PAI-1 were found in group B compared to group A, While t-PA progressively decreased with the increase of DA (r(s)=-0.45, p=0.0019), a positive relation of PAI-1 to DA was observed (r(s)=0.42, p=0.0042). A 2-fold increase of PAI-1/t-PA molar ratio in group D compared to groups A and C as well as its positive correlation with SI (r(s)=0.63, p=0.0001) indicate the displacement of balance between t-PA and PAI-1 in favour of the inhibitor with the increase of DA in RA. The involvement of inflammatory mediators in PAI-1/t-PA imbalance was proposed from the relation of fibrinolytic abnormalities with the activity of systemic inflammatory process

Comparative study of tetranectin levels in serum and synovial fluid of patients with rheumatoid arthritis, seronegative spondylarthritis and osteoarthritis

Tetranectin (TN) was assessed in paired synovial fluid (SE) and serum (S) samples from 27 patients with rheumatoid arthritis (RA), 23 with seronegative spondylarchritis (SSA) and 22 with osteoarthritis (OA). RA patients had a stronger correlation between serum and SF TN and a higher SF/S TN ratio than did SSA and OA patients. Moreover, the SF/S TN ratio exceeded 1 in most RA patients but not in SSA and OA patients, indicating the possibility of intraarticular TN synthesis in RA. A strong correlation of serum and SF TN with known inflammatory markers was observed in RA. The TN/proteinase inhibitors (PIs: alpha(1)-antitrypsin,alpha(2)-macroglobulin) molar ratio in SF was lower in RA and SSA patients to a statistically significant degree than in OA patients. In RA, in contrast to SSA and OA, this ratio correlated positively with the SF interleukin-8 (IL-8), responsible for neutrophil recruitment and degranulation, and negatively with erythrocyte sedimentation rate, serum C-reactive protein and fibrinogen, known markers of disease activity, in conclusion, patients with RA showed lower serum TN levels, a higher SF/S TN ratio and a lower SF TN/PI molar ratio than did SSA and OA patients, suggesting the implication of TN in the impaired regulation of fibrinolysis associated with the inflammatory process

Tetranectin, soluble P-selectin and VCAM-1 in the plasma of children with insulin-dependent diabetes mellitus

Objectives: Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disorder characterized by a variety of haemostatic abnormalities. The purpose of this study was to investigate the levels of tetranectin (TN), a regulator of fibrinolysis, in the plasma of IDDM children in relation to HbA1c levels and to the state of platelet and endothelial cells activation expressed by the levels of circulating P-selection (cP-selectin) and VCAM-1 (cVCAM-1). Patients and methods: TN, cP-selectin and cVCAM-1 levels were assessed by ELISA in the plasma of 75 uncomplicated IDDM children and compared with those of 33 healthy subjects. Patients were divided into subgroups A and B according to the levels of HbA1c (HbA1c less than or equal to 6.8% and HbA1c > 6.8% respectively). Results: TN levels have the tendency to be higher in IDDM children [14.98(12.50-18.10) mg/L, P = 0.0210] compared to those in healthy subjects [13.44(10.48-16.32) mg/L] and were significantly higher in subgroup B than in subgroup A [16.92(13.48-18.26) mg/L vs 13.68(11.35-14.89) mg/L respectively, P = 0.0120]. The plasma levels of cP-selectin and cVCAM-1 were significantly elevated in IDDM [301(218-401) ng/ml, P = 0.0004 and 997(814-1222) ng/ml, P = 0.0015 respectively] than in healthy subjects [201(135-243) ng/ml, and 724(602-864) ng/ml respectively]. A trend towards higher cP-selectin levels was observed in subgroup B compared to subgroup A. As regards cVCAM-1, no statistically significant difference was found between subgroups A and B. A significant correlation was found between cP-selectin and cVCAM-1 (r(s) = 0.32, P = 0.034), while no correlation was found between these variables and TN or HbA1c. However, a significant correlation was observed between TN and HbA1c (r(s), = 0.37, P = 0.011) in all IDDM patients. Likewise, a longitudinal follow up of 10 IDDM patients revealed a positive correlation between TN and HbA1c in each patient. Conclusions: These data provide evidence for VN elevation with the increase of HbA1c in uncomplicated IDDM children, suggestive of TN involvement in the haemostatic abnormalities in IDDM. The mechanism by which this would occur is discussed

Serum levels of tetranectin, intercellular adhesion molecule-1 and interleukin-10 in B-chronic lymphocytic leukemia

Background and objective: The fibrinolytic regulator tetranectin (TN), in association with the circulating intercellular adhesive molecule-1 (clCAM-1) and interleukin-10 (IL-10), may be involved in the metastatic cascade of B-chronic lymphocytic leukemia (B-CLL). Our aim was to investigate the potential usefulness of these molecules as prognostic markers in B-CLL. Design and methods: Therefore, TN, clCAM-1, and IL-10 were assessed (ELISA) in the serum of 53 B-CLL patients, classified in Binet A, B, and C stages in comparison with those in 45 healthy subjects (HS). Results: TN was significantly lower in B-CLL patients than in HS (9.63 [8.75-11.51] mg/L, 13.75 [12.56-14.64] ng/mL, respectively. p < 10(-5)), being lower (p = 0.05) in B and C stage patients (subgroup B+C) than in A stage ones (subgroup A). clCAM-1 levels were significantly higher in B-CLL patients than in HS (475.86 [355.86-593.79] ng/mL vs. 225.62 [118.49-312.83] ng/mL, respectively, p = 10-5) with a tendency for higher levels in subgroup B+C than in subgroup A. A significant correlation of clCAM-1 with lactate dehydrogenase (LDH) (r(s) = 0.532, p = 0.049), and a significant increase in clCAM-1 in B-CLL with diffuse bone marrow infiltration (BMI) compared to that in B-CLL with nondiffuse BMI (624.48 [557.24-726.55] ng/mL vs. 480.34 [368.96-590.34] ng/mL, respectively, p = 0.0172) were found. A significant negative correlation between TN and clCAM-1 (r(s) = -0.5017, p = 0.0001) was observed. IL-10 was detected in all B-CLL patients and in no HS (7.37 [5.30-10.55] pg/mL), being higher (p = 0.0153) in C than in A stage patients. A significant correlation of IL-10 with TN and clCAM-1 in subgroup B+C (r(s) = -0.659 [p = 0.014] and r(s) = 0.679 [p = 0.011], respectively) was found. Conclusions: The abovementioned findings and good performance characteristics of TN and clCAM-1 in B-CLL suggest the potential usefulness of these adhesive/recognition molecules as prognostic markers in B-CLL. The implication of these molecules along with IL-10 in the disease process deserves further study. Copyright (C) 1999 The Canadian Society of Clinical Chemists

Derangement of hemostasis in rheumatoid arthritis: association with demographic, inflammatory and metabolic factors

Disturbance of fibrinolysis is common in rheumatoid arthritis (RA), and it may be associated with the increased cardiovascular risk observed in this population. We aimed to assess coagulation derangement and investigate whether abnormalities are influenced by demographic, inflammatory or metabolic factors in patients with RA. Levels of tissue plasminogen activator (tPA), plasminogen activator inhibitor (PAI-1), fibrinogen, prothrombin fragment 1 + 2 (PF1 + 2), thrombomodulin (TM), protein C and Von Willebrand factor (vWF) were compared between 141 RA patients and 50 healthy hospital controls. Within RA, coagulation factors were assessed alongside several demographic, inflammation and metabolic indicators. RA patients had higher levels of coagulation factors than controls. After correction for age and sex, having RA predicted increased tPA (B = 0.15, P <0.001), PAI-1 (B = 0.21, P <0.001), fibrinogen (B = 0.86, P <0.001), PF1 + 2 (B = 0.20, P <0.001), and TM (B = 0.01, P = 0.03) levels. CRP correlated positively with tPA (P <0.05), fibrinogen (P <0.001), TM (P <0.05), PF1 + 2 (P <0.001) and vWF (P <0.001). Metabolic factors linked with coagulation factors were hypertriglyceridaemia (tPA, P <0.05; PAI-1, P <0.05; protein C, P <0.05) and insulin resistance (tPA, P <0.01; PAI-1, P <0.01; vWF, P <0.05). Imbalance of coagulation and fibrinolytic mechanisms is common in RA and associates with age, inflammation, and metabolic factors. Further studies may determine whether these abnormalities are the consequence of acute inflammation or markers of vascular dysfunction. © 2013 Clinical Rheumatology