Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UNIPROT:P00750 (PLA)
16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To study the effect of sex hormones on the hemostatic responses to stress, blood samples were collected before, during, and after 20 min of mental stress from 9 healthy, non-smoking female volunteers, examined in the follicular and luteal phase. Mental stress caused significant increases in heart rate, blood pressure, and plasma catecholamines. In addition, analysis of variance indicated significant changes of leukocyte count, hematocrit, fibrinogen, von Willebrand factor antigen, t-PA activity and antigen in response to the stress test. However, in contrast to a male group previously investigated, there were no significant changes in factor VII coagulant activity in either menstrual phase. Overall the responses were more pronounced in the luteal as compared to the follicular phase. The findings support the concept that both gender and physiological variations in female sex hormones may modulate hemostatic responses to psychosocial stress.
...
PMID:Hemostatic responses to mental stress during the menstrual cycle. 180 26

The effects of mental stress (a colour word conflict test, CWT) and adrenaline infusions (0.1 and 0.4 nmol kg-1 min-1) on t-PA activity, t-PA antigen, PAI-1 activity and PAI-1 antigen were studied in 18 healthy male volunteers. Furthermore, the effects of metoprolol (200 mg/day during 1 week) or placebo (double-blind cross-over study) on fibrinolytic responses to sympatho-adrenal activation, and relationships between fibrinolysis and blood lipids were investigated. Low and high dose adrenaline infusions yielding plasma adrenaline levels of 0.9 +/- 0.1 and 3.4 +/- 0.4 nmol/l, respectively, dose-dependently increased t-PA levels with a concomitant decrease in PAI-1 levels. A similar, but weaker, fibrinolytic response seemed to occur during CWT, when plasma adrenaline levels were only moderately increased (to 0.4 +/- 0.1 nmol/l). Metoprolol treatment did not influence the resting levels of the fibrinolytic variables studied, but tended to enhance the t-PA response to CWT and further reduce PAI-1 during adrenaline infusion. Metoprolol treatment was not accompanied by any rise in PAI-1 levels despite drug induced elevations of triglyceride levels. Thus, the present study shows that sympatho-adrenal activation increases fibrinolytic activity in vivo and that metoprolol treatment may have a favourable influence on this activity.
...
PMID:Influence of metoprolol treatment on sympatho-adrenal activation of fibrinolysis. 211 30

We have previously shown that plasma levels of endothelium-derived tissue-type plasminogen activator (t-PA) increase during mental stress. The aim of the study was to investigate in vivo release in an intact human muscle vascular bed. Eleven healthy young males (22-36 yrs) were studied at rest and during 10 min of mental stress (forced arithmetic). Net release or uptake were assessed by arterio-venous (AV) concentration gradients across the forearm of t-PA antigen and t-PA activity, and plasminogen activator inhibitor antigen type 1 (PAI-1). Forearm blood flow was measured by venous occlusion plethysmography. At rest, there was a positive AV-difference of t-PA activity across the forearm indicating a net release of t-PA activity of approximately 3.7 fmol x min-1 x 100 ml-1 (Wilcoxon's signed rank test vs 0, p = 0.01). However, t-PA antigen showed a variable release pattern. On the average, there was a net release of 0.17 ng x min-1 x 100 ml-1 after 60 min of rest (Wilcoxon vs 0, p = 0.07). PAI-1 antigen showed net release at rest. In response to stress, forearm blood flow increased from 1.9 to 2.9 ml x min-1 x 100 ml-1 (ANOVA, p = 0.007), and net release of t-PA activity increased to 9.8 fmol x min-1 x 100 ml-1 (ANOVA, p = 0.01 compared with rest). Arterial and venous plasma t-PA levels also increased significantly during stress (ANOVA, p < 0.01). t-PA antigen showed a similar but less pronounced release pattern during stress.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:In vivo release of tissue-type plasminogen activator across the human forearm during mental stress. 783 66

We have recently shown that mental stress increases local net release of tissue-type plasminogen activator (t-PA) across the forearm vascular bed. However, the mechanisms responsible for the t-PA release in man during stress are undefined. To study the effects of endothelial cell receptor stimulation and fluid shear stress we used the perfused forearm model to characterize the in vivo tissue plasminogen activator (t-PA) response in man to methacholine (Mch) and sodium nitroprusside (SNP), at doses calculated to cause similar degrees of vasodilation. The study was performed in 7 healthy young men (age 22-24 yrs) without hypertension, diabetes mellitus, or hypercholesterolemia. Each subject received double-blind step-wise i. a. infusions of Mch (0.1-0.8-4.0 micrograms/min) and SNP (0.5-2.5-10 micrograms/min) in randomized order. Each dose step was infused for 5 min. Forearm blood flow was assessed by plethysmography. Net release/uptake was expressed as the product of arterio-venous concentration gradient and forearm plasma flow. At pre-infusion baseline, there was a significant net release of t-PA antigen of approximately 0.9 ng x min-1 x 100 ml-1 and t-PA activity of 3.5 fmol x min-1 x 100 ml-1 across the forearm. I.a. infusion of Mch and SNP increased forearm blood flow from 1.9 to 14.9 and from 1.8 to 12.1 ml x min-1 x 100 ml-1, respectively (Mch vs SBP N.S.).(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Release of tissue-type plasminogen activator in response to muscarinic receptor stimulation in human forearm. 787 38

Hypertriglyceridemia is linked to impaired fibrinolytic function, and lipid-lowering treatment with fibric acid derivatives could hypothetically improve fibrinolysis in this condition. We therefore conducted a double-blind, placebo-controlled, crossover study of gemfibrozil treatment on fibrinolytic function in 21 men with combined hyperlipoproteinemia. Measurements were performed at rest and during mental stress and after venous occlusion. The patients had clearly disturbed fibrinolytic function, with elevated plasminogen activator inhibitor-1 (PAI-1) activity at rest ( approximately 25 U/mL; reference, <15 U/mL). Gemfibrozil reduced plasma total and VLDL cholesterol as well as all triglyceride fractions, whereas HDL cholesterol increased (P <.001 for all). Total triglyceride levels were reduced by 57 +/- 4% (from 5.3 to 2.1 mmol/L). Fasting serum insulin levels were not altered by gemfibrozil treatment. Plasma levels of PAI-1 activity and tissue-type plasminogen activator (TPA) activity or antigen were unaffected by gemfibrozil treatment both at rest and during the provocations. The levels of D-dimer, plasmin/antiplasmin complex, and fibrinogen were also uninfluenced by gemfibrozil treatment. Mental stress elevated plasma TPA (P=.0036) and lowered PAI-1 (P=.0012) activity during placebo but not gemfibrozil treatment (P=.28 and P=.17, respectively), but treatment effects did not differ by ANOVA on delta values (ie, stress minus rest). Venous occlusion reduced PAI-1 activity, whereas TPA and plasmin/antiplasmin complex increased during both treatments. Thus, gemfibrozil treatment did not improve fibrinolysis or lower fibrinogen levels in men with combined hyperlipoproteinemia despite marked reduction of plasma triglyceride levels. It seems unlikely that improved fibrinolysis explains the primary preventive effect of gemfibrozil.
...
PMID:Gemfibrozil treatment of combined hyperlipoproteinemia. No improvement of fibrinolysis despite marked reduction of plasma triglyceride levels. 862 72

We have previously shown that both mental stress and administration of the muscarinic receptor agonist methacholine induce an acute release of tissue-type plasminogen activator (t-PA) across the human forearm. There are data indicating that the regulated acute release of t-PA from the endothelium is closely interrelated with release of von Willebrand factor (vWF). The aim of the present study was to simultaneously determine basal and stimulated in vivo release rates of t-PA and vWF in an intact human muscle vascular bed. Eighteen healthy young males were studied at rest and during 10 min of mental stress (forced arithmetic). A subsample of ten subjects also received a step-wise i.a. infusion of methacholine (0.1-0.8-4.0 microg/min). Forearm blood flow was determined by venous occlusion plethysmography and interconverted to forearm plasma flow (FPF) using individual hematocrits. Net release/uptake rates of t-PA and vWF were calculated as the product of the arteriovenous concentration gradient and FPF. At rest there was a net release of both t-PA antigen and activity. In contrast, there was no significant local net release of vWF antigen across the forearm. Net release rates of t-PA roughly doubled in response to the stress test (0.4 to 0.8 and 0.2 to 0.5 ng x min(-1) x 100 ml(-1) for t-PA antigen and activity, respectively, p <0.05 for both). Local administration of methacholine induced a more than 10-fold increase in the net release rates of t-PA (0.6 to 9.6 and 0.3 to 6.6 ng x min(-1) x 100 ml(-1) at the highest dose step for antigen and activity respectively, p <0.01 for both). In contrast, neither mental stress nor local administration of methacholine induced a significant net release of vWF antigen across the forearm. The results demonstrate that the processes of acute release of t-PA and vWF are not necessarily linked in vivo in man.
...
PMID:Sympathoadrenal activation and muscarinic receptor stimulation induce acute release of tissue-type plasminogen activator but not von Willebrand factor across the human forearm. 926 90

We have observed marked interindividual differences in release rates of tissue-type plasminogen activator (t-PA) among healthy subjects. The objective of the current study was to test the hypothesis that there is an association between a genetic variation at the t-PA locus and the in vivo release rate of t-PA. Fifty-one healthy males were studied at rest in the morning and 27 of these were also subjected to a mental stress test. Net release rates of total t-PA across the forearm vascular bed were calculated as the product of the venoarterial concentration gradient and forearm plasma flow. Zygosity for an Alu-repeat polymorphism in intron 8 of the t-PA gene was determined by a polymerase chain reaction. Basal t-PA release rates differed markedly by genotype (ANOVA, P<0.05); subjects homozygous for the insertion had a significantly higher release rate (mean 10.9 ng. min-1. L-1, n=19) than both heterozygotes (4.5 ng. min-1. L-1, n=26) and subjects homozygous for the deletion (0.9 ng. min-1. L-1, n=6). After 2 minutes of mental stress release rates had increased approximately 2-fold in all groups. Arterial and venous plasma levels of t-PA were unrelated to genotype. In conclusion, the current results provide the first evidence of an association between a common genetic variation at the t-PA locus and interindividual differences in net release rates of t-PA in vivo. The relationship is not reflected by circulating steady-state plasma levels and can thus not be disclosed by conventional venous plasma sampling.
...
PMID:Gene polymorphism of t-PA is associated with forearm vascular release rate of t-PA. 997 31

Tissue plasminogen activator (tPA) promotes fibrinolysis, and impaired fibrinolysis is associated with atherosclerosis and thrombosis. Plasminogen activator inhibitor-1 (PAI-1) inhibits t-PA expression. The effects of acute laboratory stressors on tPA and tPA/PAI-1 complexes were assessed in a sample of 11 cardiac patients. Participants were randomly assigned to either a stress or relaxation condition at time 1, and the alternative condition at time 2. Blood samples were taken before (pre) and after (post) each session and participants completed a battery of psychological questionnaires. Two-way repeated-measures analysis of variance revealed a statistically significant decrease in tPA (P = 0.01) and tPA-PAI-1 complexes (P = 0.04) during the mental stress condition. Anger-in had a strong relationship to decreases in tPA/PAI-1 levels in the stress condition (r = 0.68, P < 0.05). Relaxation had no significant effect on tPA and tPA/PAI-1 levels. These data suggest that decreased fibrinolysis mediates the relationship between mental stress and atherosclerosis.
...
PMID:Acute psychological stress decreases plasma tissue plasminogen activator (tPA) and tissue plasminogen activator/plasminogen activator inhibitor-1 (tPA/PAI-1) complexes in cardiac patients. 1113 73

It is established that sympathetic neurons can synthesize, transport and store tissue plasminogen activator (t-PA) within axon terminals in the smooth muscle of vessel walls. Moreover, sympathetic excitations (e.g. physical and mental stress) are known to induce an acute release of t-PA into the circulation. However, relatively little is known about the nature and extent of sympathetic nervous system involvement in the release process. We inquired whether a chemical sympathectomy will alter the release of t-PA into the blood, and the intrinsic release of stored t-PA from isolated whole vessel explants. A long-term sympathectomy was induced in adult Sprague-Dawley rats by injection of guanethidine during a 5-week course. The destruction of ganglion neurons and vessel wall axons was verified immunohistochemically. t-PA release was assayed as the free activity in hind limb plasma and explant culture medium. Following sympathectomy: (i) the basal t-PA activity in plasma was 70% less than controls (2.92 +/- 1.96 versus 9.33 +/- 1.72 IU/ml; </= 0.001); (ii) the acute release from isolated vessels induced by bradykinin or phenylephrine was comparably reduced; and (iii) the greatest reductions occurred in densely innervated small vessel explants. The results provide new support for an autonomic regulation of neural t-PA release into the vessel wall matrix and blood of densely innervated thin-walled microvessels.
...
PMID:Additional evidence that the sympathetic nervous system regulates the vessel wall release of tissue plasminogen activator. 1219 98

Low socioeconomic status (SES) and psychological stress are associated with increased risk of coronary heart disease, and both may influence haemostatic responses. Von Willebrand factor (vWF), Factor VIII, plasma viscosity, haematocrit, blood viscosity, tissue plasminogen activator (t-PA) and fibrin D-dimer were measured at rest and following stressful tasks in 238 middle-aged British civil servants. SES was defined by grade of employment. Lower SES was associated with higher resting vWF, Factor VIII and plasma viscosity. Psychological stress stimulated increases in haemostatic and rheological factors. Initial stress responses did not vary with SES, but Factor VIII, plasma viscosity and blood viscosity remained more elevated 45 minutes post-stress in lower SES participants. High blood pressure stress reactivity was also associated with greater haemostatic responses. We conclude that lower SES is characterised by more prolonged elevations in procoagulant responses following psychological stress, and that these processes might contribute to increased cardiac risk.
...
PMID:Prolonged elevations in haemostatic and rheological responses following psychological stress in low socioeconomic status men and women. 1254 Sep 57


1 2 Next >>

---