Bacterial endocarditis in a child presenting with acute arterial ischemic stroke: should thrombolytic therapy be absolutely contraindicated?

Thrombolysis is considered to be contraindicated in acute ischemic stroke secondary to infective endocarditis (IE). We report a 12-year-old female who presented with acute dense right hemiparesis and aphasia. Cranial magnetic resonance imaging and angiography showed multiple diffusion-restricted lesions in the left hemisphere and absence of flow in the left internal carotid artery. She was treated with intra-arterial tissue plasminogen activator within 6 hours of her presentation. Subsequently she was diagnosed with pneumococcal endocarditis and underwent debridement of vegetations and patch repair of the mitral valve. The patient did not have hemorrhagic complications following thrombolytic therapy or surgery. Pathological analysis of the mitral valve vegetations revealed mostly fibrin thrombus. Follow-up imaging showed complete recanalization of the left internal carotid artery, and the patient had a remarkable neurological recovery. This is the first case report of successful intra-arterial thrombolytic therapy in childhood IE-related stroke. We believe that thrombolytic therapy contributed to a favorable outcome in our patient and may be safe in selected patients with childhood IE-related acute ischemic stroke.

The effect of submaximal exercise on fibrinolysis.

We studied the relationship between sustained submaximal exercise, increased tissue plasminogen activator (t-PA) levels and decreased hepatic clearance of t-PA. Six healthy male volunteers exercised for 35 min while receiving constant rate infusions of either saline or two different doses of recombinant t-PA for 90 min (40 min before, 35 min during and 15 min after exercise). Liver blood flow was estimated simultaneously by constant rate indocyanine green infusion. Since t-PA is cleared rapidly by the liver in direct proportion to liver blood flow, it was expected that a significant decrease in liver blood flow during sustained submaximal exercise would be associated with a proportional increase in plasma t-PA. During submaximal exercise with a saline (placebo) infusion, steady-state t-PA antigen increased from a resting baseline of 6.3 +/- 3.1 to 15.1 +/- 5.1 ng/ml; with a 20 microg/min t-PA infusion, t-PA antigen increased from 33 +/- 12 to 84 +/- 25 ng/ml during exercise; and with a 40 microg/min t-PA infusion, t-PA antigen increased from 77 +/- 38 to 166 +/- 42 ng/ml during exercise. During submaximal exercise, liver blood flow fell on average 71, 68 and 70%, respectively, during the three procedures, while calculated t-PA clearance decreased on average 59, 59 and 53%. t-PA concentration versus time curves, displayed in proportional units, were similar. The comparable relative increases in endogenous and exogenous t-PA with simultaneous proportional decreases in liver blood flow suggests that diminished hepatic t-PA clearance is the major cause of increased t-PA concentration and blood fibrinolytic activity enhancement during sustained submaximal exercise.

Increased urinary albumin excretion, endothelial dysfunction, and chronic low-grade inflammation in type 2 diabetes: progressive, interrelated, and independently associated with risk of death.

In 328 type 2 diabetic patients followed for 9.0 years (mean), we investigated whether endothelial dysfunction and chronic inflammation (estimated from plasma markers) can explain the association between (micro)albuminuria and mortality. Of the patients, 113 died. Mortality was increased in patients with baseline microalbuminuria or macroalbuminuria (odds ratios as compared with normoalbuminuria, 1.78 [P < 0.05] and 2.86 [P < 0.01]) and in patients with soluble vascular cell adhesion molecule 1 in the third tertile and C-reactive protein in the second and third tertiles (odds ratios as compared with the first tertile, 2.05 [ P < 0.01], and 1.80 [P < 0.05] and 2.92 [ P < 0.01]). These associations were mutually independent. The mean yearly change in urinary albumin excretion was 9.4%; in von Willebrand factor, 8.1%; in tissue-type plasminogen activator, 2.8%; in soluble vascular cell adhesion molecule 1, 5.2%; in soluble E-selectin, -2.3%; in C-reactive protein, 3.8%; and in fibrinogen, 2.3%. The longitudinal development of urinary albumin excretion was significantly and independently determined by baseline levels of and the longitudinal development of BMI, systolic blood pressure, serum creatinine, glycated hemoglobin and plasma von Willebrand factor (baseline only), soluble E-selectin (baseline only), tissue-type plasminogen activator, C-reactive protein, and fibrinogen. The longitudinal developments of markers of endothelial function and inflammation were interrelated. In type 2 diabetes, increased urinary albumin excretion, endothelial dysfunction, and chronic inflammation are interrelated processes that develop in parallel, progress with time, and are strongly and independently associated with risk of death.

Enhanced expression of plasminogen activator inhibitor 1 in patients with nephrotic syndrome.

Hypercoagulability is present in patients with nephrotic syndrome. However, alterations in coagulation and fibrinolysis reflected in the glomeruli and urine are not fully understood. We examined plasma and urine concentrations of tissue-type plasminogen activator (tPA) and type 1 plasminogen activator inhibitor (PAI-1) in 33 patients with nephrotic syndrome (nephrotic group). We compared these concentrations with the concentrations in 30 nonnephrotic patients with chronic glomerulonephritis (nonnephrotic group) and with the concentrations in 30 healthy volunteers (control group). We also examined fibrin/fibrinogen degradation products in serum and urine and plasma D-dimers. The expression of tPA and PAI-1 was examined in isolated glomeruli using RT-PCR methods. Deposition of fibrinogen/fibrin-related antigen was observed by direct immunofluorescence. The incidence of fibrinogen/fibrin-related antigen deposition in the nephrotic group was significantly higher than that in the nonnephrotic group. The concentrations of fibrin/fibrinogen degradation products in serum and urine and of plasma D-dimers were significantly elevated in the nephrotic group as compared with the nonnephrotic and control groups. The plasma concentrations of tPA in the nephrotic group were significantly higher than those in the control group. The urinary excretion of tPA in the nephrotic group was also significantly higher than in the nonnephrotic and control groups. The urinary excretion of PAI-1 in the nephrotic group was higher than that in the control group. The ratio of PAI-1 mRNA to tPA mRNA in glomeruli was increased in the nephrotic group as compared with the nonnephrotic group. These results indicate that the fibrinolytic activity is increased in patients with nephrotic syndrome despite urinary losses of tPA. However, a relatively enhanced expression of PAI-1 may be involved in the intraglomerular fibrinogen/fibrin-related antigen deposition seen in nephrotic syndrome.

[Fibrinolytic activity of the urine during chronic glomerulonephritis and amyloidosis]. / Fibrinoliticheskaia aktivnost' mochi pri khronicheskom glomerulonefrite i amiloidoze.

Correlative interconnections between plasminogen activator (PA) activity (fibrin plate method) and level of urokinase antigen (Ag UAP) and tissue PA antigen (Ag TAP) in urine and blood (ELISA) were studied in 60 patients with chronic glomerulonephritis (CGN) and 38 patients with amyloidosis. The high degree of positive correlation between blood and urine initial PA activity and Ag UAP content was found. This suggests the possible leading role of UAP in formation of the basal fluctuations of fibrinolytic activity in blood and urine. High degree of correlation--r = +0.84 and p < 0.001--was found between blood Ag UAP and urine Ag TAP in amyloidosis only. The functional protein loading probe revealed great importance of high urine and blood AP activity in realizing of ultrafiltration renal process--in CGN and amyloidosis.

[Tissue type plasminogen activator antigen in urine of patients with bladder cancer]. / Antygen tkankowego aktywatora plazminogenu w moczu chorych na raka pecherza moczowego.

In urine of 25 patients with bladder carcinoma the antigen of tissue type plasminogen activator (t-PA) was assessed. The level of t-PA was much higher in patients with bladder carcinoma in comparison with a control group. We also analyzed the level of t-PA between patients with superficial and invasive bladder carcinoma the level of t-PA was higher. In conclusion, there is t-PA in urine of patients with bladder carcinoma and its level is correlated with staging of neoplasm.

[Tissue plasminogen activator in urine of patients with prostatic carcinoma and benign prostatic hyperplasia]. / Antygen tkankowego aktywatora plazminogenu w moczu chorych na raka i lagodny rozrost gruczolu krokowego.

In the 20 patients with prostatic carcinoma (PC) and the 18 with benign prostatic hyperplasia (BPH) the level of tissue type plasminogen activator (t-PA:Ag) was examined. As a compared group consisted of 24 healthy volunteers. In the urine of examined patients with PC and BPH and control the t-PA:Ag was absent or present only in trace amounts. We concluded that the t-PA:Ag in the urine of patients with PC can not be as a marker in the diagnosis of prostatic diseases especially in the prostatic carcinoma.

Post-operative blood loss after transurethral prostatectomy is dependent on in situ fibrinolysis.

OBJECTIVE: To evaluate whether post-operative blood loss in patients with benign prostatic hyperplasia, undergoing transurethral resection of the prostate (TURP), depends on in situ fibrinolysis in urine, and to determine the relative contributions of the urokinase and tissue-type plasminogen activator systems. PATIENTS AND METHODS: TURP was performed in 24 men (median age 68.5 years, range 52-78) and the weight of resected tissue, the operative and post-operative blood loss determined. The concentrations of the urokinase- (u-PA) and tissue-type plasminogen activator (t-PA)-related fibrinolysis in their urine was followed using sensitive and specific assays, and the changes related to post-operative blood loss. Measurements of the urinary concentrations of free t-PA activity, t-PA antigen, free u-PA activity, u-PA antigen and fibrin degradation products (FbDP) were determined and the area under the curve for each of these quantities correlated with the post-operative blood loss. RESULTS: The post-operative blood loss correlated significantly with the per-operative loss (P = 0.047) and the weight of resected tissue (P = 0.029). There was a highly significant correlation between the area under the curve of FbDP in the urine and the post-operative blood loss (P < 0.005), while there was no significant positive correlation between the PA concentration or activity in the urine and post-operative blood loss. There was a significant correlation between the urinary t-PA activity and the amount of FbDP in the urine (P = 0.047), and a significant correlation between the weight of resected tissue and the amount of FbDP in the urine (P = 0.014). CONCLUSION: The post-operative blood loss after TURP is significantly related to an increase of the urinary fibrinolytic activity and the enhanced fibrinolytic activity is probably caused by t-PA.

Platelet function and fibrinolytic activity in hypertensive and normotensive sleep apnea patients.

Platelet function and fibrinolytic activity was studied during rest and after ergometric exercise in 13 hypertensive or normotensive patients with obstructive sleep apnea (OSA) and in 10 sex- and weight-matched controls. All patients had undergone a complete polysomnography for the diagnosis of OSA. The controls did not undergo any sleep investigation but had no history of snoring or witnessed apneas during sleep. On antihypertensive drug wash-out, two of the patients were normotensive, whereas 11 had mild to moderate hypertension. Platelet aggregation measured by adenosine 5'-diphosphate- or adrenaline-induced aggregation, platelet factor-4 or beta-thromboglobulin did not differ between patients and controls. During exercise beta-thromboglobulin decreased significantly in both OSA patients and controls. Plasma tissue plasminogen activator activity was similar in OSA patients and controls and increased significantly in both groups after exercise. Plasminogen activator inhibitor type 1 (PAI-1) was 18.4 +/- 3.6 IU/ml in OSA patients compared with 8.2 +/- 1.7 IU/ml in controls (p < 0.029) during rest, indicating decreased fibrinolytic activity. The difference between groups remained after exercise (p < 0.017). Blood pressure elevation was more common and body mass index (BMI) was higher in patients with OSA, but there was no direct relation between blood pressure level or BMI and PAI-1. Nevertheless, differences between groups were smaller when blood pressure and obesity were accounted for. It is concluded that patients with OSA may exhibit decreased fibrinolytic activity. Low fibrinolytic activity may represent a confounding pathophysiological mechanism behind the high incidence of myocardial infarction and stroke in patients with OSA.

Simultaneous determination of free tissue-type and free urokinase-type plasminogen activators in biological fluids by a solid-phase immunoassay.

Tissue-type and urokinase-type plasminogen activators (t-PA and u-PA) coexist in numerous biological fluids, where their fibrinolytic activities are determined by the concentration of the free, uncomplexed species. A simple, sensitive method has been developed for the simultaneous determination of free t-PA and u-PA concentrations in biological fluids using a solid-phase immunoassay. Microtiter plates were coated with polyclonal goat antibodies and incubated with PA standards or unknown samples. The absorbed PAs were then assayed by incubation with a mixture of plasminogen, poly-L-lysine, and the chromogenic substrate H-D-norleucylhexahydrotyrosyllysine-p-nitroanilide. Free t-PA and free u-PA were detectable in human plasma and urine, and in conditioned media from different endothelial cell cultures. The method is sensitive, with lower limits of quantitation being 0.76 mU/ml (1.25 pg/ml) for free t-PA and 0.16 mU/ml (2.0 pg/ml) for free u-PA. There was no cross-reaction between the two PA species and the recovery in plasma was greater than 95% for both. The intra- and interassay coefficients of variation for t-PA and u-PA were 3.5-12.2 and 3.2-11.3%, and 2.4-11.8 and 1.6-10.4%, respectively. The presence of PA-inhibitor complexes and PA inhibitors in biological fluids did not interfere with the assay. Application of the assay has demonstrated that free u-PA levels are several fold higher than free t-PA levels in human plasma and in conditioned media of human vascular endothelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Urinary tissue plasminogen activator in renal disease.

Whereas plasminogen activator of the tissue-type (t-PA) is present in extracts of kidney parenchyma, only small amounts of the enzyme can be detected in normal urine where the major plasminogen activator is of the urokinase-type (u-PA). These observations suggest the existence of physiological or anatomical barriers that effectively confine t-PA to renal tissue and exclude it from the urine. We examined the notion that disease might breach these barriers and so lead to the appearance of abnormal amounts of t-PA in the urine. Under the conditions of the simple fibrinolytic assay that we have developed, urine samples from 30 normal subjects did not contain detectable amounts of t-PA whereas we were able to demonstrate t-PA in samples from 43 of 65 patients with various forms of renal disease. When positive, therefore, tests for the presence of t-PA in human urine provide evidence for renal disease that may not otherwise be apparent.

Characterization of a tissue-type plasminogen activator from porcine urine.

Porcine urine, unlike human urine, does not contain detectable amounts of urokinase-type plasminogen activator (u-PA). The plasminogen activator present in porcine urine is of tissue-type (t-PA) as identified by the following criteria. (1) Porcine urine PA exhibits an Mr of 65,000 similar to the Mr of human t-PA (64-70,000) but distinct from the Mr of human u-PA (55,000). (2) Antibodies against human t-PA bind and inhibit crude and purified porcine urine PA, while human u-PA-specific antibodies do not react with porcine urine PA. (3) Plasminogen activation by porcine urine PA is markedly stimulated in the presence of fibrinogen fragments. (4) Porcine urine PA activity is not affected by concentration of amiloride substantially suppressing human u-PA activity.

[Intraglomerular coagulation and fibrinolysis in human primary glomerular diseases].

It is a well known fact that intraglomerular coagulation plays an important role in the development of human primary glomerular diseases. However, the precise mechanism of intraglomerular coagulation, and intraglomerular coagulability and/or fibrinolytic activity remains obscure. The present study was aimed to elucidate the role of the intraglomerular coagulation and fibrinolysis in human primary glomerular diseases. Subjects enrolled in this study were 27 patients with minimal change nephrotic syndrome (MCNS), 14 patients with focal glomerular sclerosis (FGS), 36 patients with membranous nephropathy (MN), 161 patients with mesangial proliferative glomerulonephritis (mesPGN), 9 patients with membranoproliferative glomerulonephritis (MPGN), and 40 healthy volunteers as controls. Normal human renal cortex as controls of isolated intraglomerular plasminogen activator activity (PAA) was obtained at the time of nephrectomy from the normal pole of kidneys removed because of an opposite pole tumor. Urinary urokinase (UK), fibrinopeptide A (FPA) and fibrinopeptide B beta 15-42 (B beta 15-42) antigens were measured by RIA. Urinary tissue plasminogen activator (t-PA) antigen was measured by ELISA. Urinary fibrin/fibrinogen degradation products (FDP) were measured by latex agglutination method. Moreover, PAA was measured by 125I-fibrin films. The following results were obtained: 1) In primary glomerular diseases, levels of urinary UK and t-PA were significantly lower than those in healthy volunteers, 2) Urinary UK and t-PA showed gradual decrease along with the development of mesangial proliferation, 3) Urinary UK and t-PA were significantly correlated with both the urinary FPA and B beta 15-42, 4) In mesPGN and FGS, PAA was significantly lower than that in normal controls, 5) PAA was significantly correlated with urinary UK, t-PA, FPA and B beta 15-42, 6) Urinary UK and t-PA in the patients with urinary FDP were significantly lower than those in patients without urinary FDP, 7) Urinary UK, t-PA and PAA were significantly lower in patients with intraglomerular fibrin deposition than those in patients without fibrin depositions. These findings suggest that the decrease of urinary UK and t-PA levels and the diminution of isolated intraglomerular plasminogen activator activity contribute to the progression of primary glomerular diseases.

[Urinary tissue-type plasminogen activator (tPA) in renal transplant patients].

We have previously suggested that an appearance of FDP D-dimer fragment into the urine predicts the reversibility of acute renal transplant rejection. In the present study, we observed urinary tissue-type plasminogen activator (tPA), which is a fibrinolytic enzyme and produces D-dimer, in 51 renal transplantation patients. Urinary tPA values are generally higher in transplantation patients except on chronic rejection than in healthy controls. High values just before onset of rejection (increase of serum creatinine value), deterioration at onset phase and gradual elevation from peak phase toward recovery phase were observed in urinary tPA of 6 reversible acute rejection episodes. Urinary D-dimer values changed following urinary tPA values in serial observation of 2 cases. In conclusion, immunological reaction accompanying by functional and organic renal impediments may result in loss of fibrinolytic activity, decrease in urinary tPA and D-dimer. This findings suggest theoretically that the supplemental tPA administration prevents the progression of rejection reaction.

Sites of synthesis of urokinase and tissue-type plasminogen activators in the murine kidney.

Kidneys have long been recognized as a major source of plasminogen activators (PAs). However, neither the sites of synthesis of the enzymes nor their role in renal function have been elucidated. By the combined use of zymographies on tissue sections and in situ hybridizations, we have explored the cellular distribution of urokinase-type (u-PA) and tissue-type (t-PA) plasminogen activators and of their mRNAs in developing and adult mouse kidneys. In 17.5-d old embryos, renal tubules synthesize u-PA, while S-shaped bodies produce t-PA. In the adult kidney, u-PA is synthesized and released in urine by the epithelial cells lining the straight parts of both proximal and distal tubules. In contrast, t-PA is produced by glomerular cells and by epithelial cells lining the distal part of collecting ducts. The precise segmental distribution of PAs suggests that both enzymes may be implicated in the maintenance of tubular patency, by catalyzing extracellular proteolysis to prevent or circumvent protein precipitation.

Substrate specificity of tissue-type and urokinase-type plasminogen activators.

Recent studies suggest that plasminogen activators not only hydrolyse a specific arginine-valine bond in plasminogen, but may also cleave other proteins such as fibronectin. We studied the substrate specificity, particularly the preference for arginyl over lysyl peptide bonds, of tissue-type plasminogen activator (t-PA) as well as of two-chain urokinase-type plasminogen activator (u-PA). The arginine/lysine preference was determined with three pairs of tripeptidyl-p-nitroanilide substrates having either arginine or lysine in the P1 position and varied from 5.2 to 14.1 for u-PA and from 55.6 to 99.8 for t-PA. It was concluded that both t-PA and u-PA preferred arginyl to lysyl peptide bonds. However, u-PA had a significantly lower arginine/lysine preference than t-PA, indicating that u-PA represents a less specific proteinase. This may point to functions of u-PA other than plasminogen activation, which involve cleavage of lysyl bonds.

Urinary UK, t-PA and urinary trypsin inhibitor in health and glomerular diseases.

The concentrations of two different plasminogen activators(PAs), urokinase (UK), tissue-type plasminogen activator (t-PA) and urinary trypsin inhibitor (UTI) were determined in the urine and blood from 48 normal subjects and 92 patients with glomerulonephritis using highly sensitive enzyme immunoassay (EIA). The values of UK clearance were approximately 1.5-fold larger than those of creatinine clearance and at least 60.8% of UK was reabsorbed in the renal tubules, which suggest that one of major secretion site of UK is located in the outer region of the glomerular basement membrane (GBM), that is glomerular epithelium. Decreased urinary excretion of UK was observed in the glomerular disease depending on their severity and correlated with the increasing degree of FDP D-dimer excretion. On the other hand, the values of t-PA clearance were quite smaller than those of creatinine clearance, which suggest that urinary t-PA originated from the blood circulation or the inner side of the GBM (possibly glomerular endothelium) and filtrated from the GBM. Like UK, urinary t-PA also decreased in glomerular diseases. UTI which is highly anionic and has a comparable size with albumin was excreted increasingly in glomerulo-nephritis due to loss of the anionic charge barrier of the GBM. No significant correlations were noted between UTI excretion and UK or t-PA excretion.

Determination of tissue type plasminogen activator in the glomeruli of patients with IgA nephropathy.

The detection, by immunofluorescence, of tissue type plasminogen activator (t-PA) in the glomeruli of 50 patients with IgA nephropathy was described. Patients with t-PA deposits revealed a higher frequency in the glomerular deposition of fibrin and/or fibrinogen than did patients without t-PA deposits. There also was a distinct relationship between the level of serum t-PA and the degree of renal tissue injury in patients with glomerular t-PA deposits. It was concluded that the deposition of t-PA along with fibrin and/or fibrinogen might reduce the effectiveness of fibrinolysis in the glomeruli of patients with IgA nephropathy.