Thrombomodulin prolongs thrombin-induced extracellular signal-regulated kinase phosphorylation and nuclear retention in endothelial cells.

On endothelial cells, thrombin binds to thrombomodulin (TM), an integral membrane-bound glycoprotein, and to protease-activated receptors (PARs). Thrombin binding to TM modulates endothelial cell and smooth muscle cell proliferation mediated through PAR1. We studied the phosphorylation and nuclear translocation of extracellular signal-regulated kinases (ERKs) 1 and 2 in human umbilical vein endothelial cells activated by thrombin. Thrombin and thrombin receptor-activating peptide (TRAP)-induced DNA synthesis were significantly inhibited by PD98059, an inhibitor of ERK phosphorylation. Immunoblots of phosphorylated ERKs (pERKs) and immunocytochemical studies of pERK localization revealed differences in the signal generated by thrombin and TRAP. After a short activation (15 minutes), the phosphorylation and the intracellular localization of pERKs were the same with the 2 agonists. After 4 hours, however, pERKs were visualized in the nuclei of thrombin-activated cells but barely detectable in TRAP-activated cells. Moreover, after 4 hours, the pERKs were visualized in the nuclei of cells stimulated by TRAP in the presence of a thrombin mutant that bound to TM, whereas they were around the nuclei in cells stimulated by thrombin in the presence of a monoclonal antibody preventing thrombin binding to TM. The results demonstrate that ERKs are involved in human umbilical vein endothelial cell DNA synthesis mediated by PAR agonists, that the duration of pERK nuclear retention is in inverse ratio to the mitogenic response, and that in addition to its role in the regulation of blood coagulation, TM acts as a thrombin receptor that modulates the duration of pERK nuclear retention and cell proliferation in response to thrombin.

Thrombomodulin modulates the mitogenic response to thrombin of human umbilical vein endothelial cells.

Thrombin interacts with its receptor and thrombomodulin on endothelial cells. We evaluated the respective roles of these two proteins on human umbilical vein endothelial cell (HUVEC) growth by comparing thrombin, S195A (a mutant thrombin in which the serine of the charge stabilizing system had been replaced by alanine), and the receptor activating peptide (TRAP). Thrombin and TRAP induced DNA synthesis (half maximal cell proliferation with 5 nM and 25 microM, respectively), whereas S195A thrombin was inactive, inferring that growth is mediated through the thrombin receptor. Surprisingly, cells stimulated by TRAP exhibited a maximal proliferation twice greater than that obtained with thrombin. Combination of thrombin and TRAP resulted in a mitogenic response higher than by thrombin alone, but lower than by TRAP alone. The role of thrombomodulin was evaluated by adding an anti-thrombomodulin antibody, which prevents formation of the thrombin-thrombomodulin complex. Antibody did not interfere with cell proliferation induced by TRAP, but enhanced that induced by thrombin. We conclude that formation of the thrombin-thrombomodulin complex restrains HUVEC proliferation mediated through the thrombin receptor.

Noninvasive estimation of systolic pulmonary artery pressure using Doppler echocardiography in patients with chronic obstructive pulmonary disease.

In patients with acquired or congenital heart diseases, the systolic pulmonary artery pressure (PAPs) can be predicted using continuous-wave Doppler ultrasound (CWD) measurement of the peak velocity of a tricuspid regurgitation (TR) jet. The aim of this study was to determine whether CWD could be used to accurately estimate PAP in patients with chronic obstructive pulmonary disease (COPD). In 41 patients with stable COPD, we prospectively performed CWD and right heart catheterization. The mean value of PAPs for the entire group was 38.5 +/- 14.9 mm Hg. Pulmonary arterial hypertension (PAPs greater than or equal to 35 mm Hg) occurred in 51 percent (21/41) of patients. Doppler estimation of PAP was impossible in 34 percent (14/41) because of poor signal quality (n = 3), absence of Doppler-detected TR (n = 8), and inadequate TR Doppler signal (n = 3). The PAP could be estimated in 66 percent (27/41) of patients. A statistically significant correlation was found between the Doppler-estimated PAP and the catheter-measured PAPs (r = 0.65; p less than 0.001; SEE = 9 mm Hg). Therefore, CWD appears to be useful for the noninvasive estimation of PAP in patients with COPD. However, this method is associated with two limitations: (1) the high percentage of patients in whom the PAP cannot be estimated by CWD, mainly because of the absence of Doppler-detected TR, and (2) the high value of the standard error of the estimate. The combination of CWD with other Doppler methods should increase the feasibility and accuracy of Doppler echography for the prediction of PAP in patients with COPD.

Renal effects of low-dose dopamine during vasopressor therapy for posttraumatic intracranial hypertension.

OBJECTIVE: To investigate the effects of low-dose dopamine (Dop) on renal hemodynamics and function in patients with brain trauma receiving norepinephrine (NE). DESIGN: Prospective clinical study. SETTING: Surgical intensive care unit of a university hospital. PATIENTS: 20 stable, non-septic, mechanically ventilated, sedated patients with brain trauma and normal renal function treated with intravenous NE (0.11-0.65 microg/kg per min) to maintain an adequate cerebral perfusion pressure (> 60 mmHg). INTERVENTIONS: Two successive 1-h study periods with NE alone then NE + Dop (2 microg/kg per min). During each period, creatinine (Cl(CREAT)), sodium (Cl(Na)), potassium (Cl(K)), osmolar (Cl(OSM)) and free water (Cl(H2O)), clearances were measured in all the patients. Effective renal blood flow (ERBF, para-aminohippurate clearance) and glomerular filtration rate (GFR, inulin clearance) were measured in 7 of the 20 patients. RESULTS: Dop during NE infusion induced increases in urine flow and natriuresis which were not correlated with possible changes in arterial pressure. Cl(CREAT), GFR and their difference remained unchanged, whereas ERBF tended to increase. Fractional sodium excretion [100 x (Cl(Na)/Cl(CREAT)] and C1(K) increased during Dop infusion. CONCLUSION: The mechanism of Dop-induced natriuresis during NE infusion in brain trauma patients seems mainly related to a direct tubular effect of the drug.

Platelets induce human umbilical vein endothelial cell proliferation through P-selectin.

We studied whether platelets could participate in the endothelial cell monolayer regeneration in the case of a vessel damage. Incorporation of [3H]-thymidine into the DNA of human umbilical vein endothelial cells (HUVECs) was measured after 48 h of co-incubation with platelets. The effect of platelets was compared to that of platelet-free supernatants from thrombin-activated platelets that had secreted their active granule constituents. Platelets dose-dependently induced HUVEC proliferation. Platelets preactivated by thrombin induced similar proliferation as did unactivated platelets (proliferation factor = 7 - 8), indicating that preactivation of platelets was not required. Platelets fixed with paraformaldehyde had no effect, suggesting that the platelet mitogenic effect required a mobile, alive membrane. Ketanserine and suramin reduced by at most 30 % the platelet-induced proliferation; supernatants of thrombin-activated platelets caused only minor proliferation (proliferation factor = 2), suggesting that secreted 5-hydroxytryptamine and growth factors poorly contributed to the proliferative effect. When the co-incubation was performed in the presence of an anti P-selectin antibody, the platelet-induced HUVEC proliferation was inhibited. The results suggest that platelet adhesion participate in the control of the endothelial regeneration and that platelet P-selectin is a molecular determinant of the proliferative signal.

[Premature rupture of the membranes. Apropos of 169 cases selected from the maternity ward of Boucicaut Hospital]. / La rupture prématurée des membranes. A propos de 169 observations relevées à la Maternité de l'Hôpital Boucicaut.

The authors present a retrospective study of 169 cases of premature rupture of the membranes. The diagnosis was made before there was any marked flow of liquor and before labour had started. The authors show that the neonatal infection rate was 12.42%. They first defined their criteria for diagnosing neonatal infection and show what risks are involved because of premature rupture of the membranes. It would appear that these are more likely to occur when there is urinary tract infection and the mother has a fever. On the other hand using prophylactic antibiotic treatment does not seem to be effective at preventing these infections. There was no case of neonatal infection when the liquor was sterile and bacteriological observation of this does seem to be important, whatever the cause. Table V shows the management that should be undertaken when premature rupture of the membranes occurs at different stages of the pregnancy in view of the findings from this study. Delivery should not be undertaken before the 32nd week but it can be brought about between the 32nd and 34th week when the liquor is infected. No tocolytic agent was used after the 34th week. In each of these cases examination of the liquor gives an indication as to which antibiotic should be used against the bacteria that had been found.

[Total serum IgE: normal pediatric values using the FAST IgE fluoroimmunoenzymatic technic]. / IgE totales sériques: valeurs usuelles en pédiatrie par la technique fluoro-immuno-enzymatique IgE FAST.

This reports covers the application to paediatrics of total IgE determination by the means of a new direct, sandwich type, fluorescence enzyme immuno-assay (Fluoro-allergo sorbent test:FAST IgE). The technical process is adapted for usual determinations, in case of infants and young children, of low normal rates with a good sensitivity, and of high pathological rates. IgE total usual values are established by the FAST IgE test from serums of healthy children, aged from one day to 14 years. Seven age groups are to be distinguished.

Hepatic plasma flow during sodium nitroprusside-induced hypotension in humans.

Changes in hepatic plasma flow (HPF) during sodium nitroprusside (SNP) induced hypotension were studied in 14 patients undergoing intracranial aneurysm surgery under neurolept anesthesia. Patients were monitored with the use of a radial artery catheter and a thermistor-tipped Swan-Ganz catheter. Hypotension was induced with incremental increases in the rate of SNP infusion until a stable mean arterial pressure (MAP) 35-55 mmHg had been achieved. In one group (Group A) of 10 patients, indocyanine green (ICG) clearance was determined simultaneously with hemodynamic variables, before and during SNP hypotension. In a second group (Group B) of four patients, a catheter was inserted into a hepatic vein to determine the ICG hepatic extraction (HE) coefficient. In Group A, MAP decreased from 73 +/- 10 (SD) to 41 +/- 9 mmHg, while cardiac index (CI) decreased in six patients and increased in four patients. However, the mean value of CI did not change significantly. The mean value of ICG clearance was not significantly affected by SNP hypotension. Nevertheless, a positive linear correlation existed between individual variation in CI and ICG clearance (r = 0.96). On the other hand, no correlation was noted between the change in MAP and ICG clearance. In Group B patients, the ICG HE coefficient remained unchanged during SNP hypotension, suggesting that ICG clearance varies only according to the variation in HPF. In conclusion, this study demonstrated that HPF did not decrease, despite a range of 20-60% decrease in blood pressure when CI is maintained during SNP hypotension.

Theophylline intoxication following viloxazine induced decrease in clearance.

A case is reported of theophylline intoxication due to a dramatic decrease in theophylline clearance following concomitant administration of viloxazine.

Detection of pulmonary hypertension by Doppler echocardiography of the inferior vena cava in chronic airflow obstruction.

Pulsed Doppler echocardiography of the inferior vena cava is an accurate method for the diagnosis of tricuspid regurgitation and impaired right ventricular compliance, two features of pulmonary hypertension. The purpose of this study was to assess the value of Doppler echocardiography of the inferior vena cava for the detection of pulmonary arterial hypertension in patients with chronic obstructive lung disease. Pulse Doppler echocardiography of the inferior vena cava and right heart catheterisation were performed in 29 patients with severe chronic obstructive lung disease. The mean pulmonary arterial pressure was 27 (10) mm Hg for the entire group; 62% of patients (18/29) had pulmonary arterial hypertension (mean pulmonary arterial pressure greater than 20 mm Hg). An adequate Doppler signal could be obtained in 25 of the 29 patients (86%). Pulsed Doppler echocardiography of the inferior vena cava gave normal results in 10 patients and disclosed tricuspid regurgitation in seven patients, impaired right ventricular compliance in seven patients, and both of these abnormalities in one patient. An abnormal Doppler echocardiogram of the inferior vena cava (tricuspid regurgitation or impaired right ventricular compliance, or both) predicted the presence of pulmonary arterial hypertension with a sensitivity of 87% and a specificity of 80%. These results suggest that pulsed Doppler echocardiography of the inferior vena cava may be a useful though imperfect method of detecting pulmonary arterial hypertension in patients with chronic obstructive lung disease.

Evidence for chestnut pollinosis in Paris.

The existence of chestnut pollinosis in Paris is not generally accepted in spite of the production of very large quantities of chestnut pollen in July. We carried out systematic skin-prick testing with chestnut pollen on 81 patients seen in the allergology department. The results were positive in 17 of the 47 patients presenting seasonal symptoms and in none of the 34 patients with perennial symptoms (chi 2 test = 12.91, P < 0.001). Eight of the 17 positive patients had sIgE levels above 300 IU/ml, 15 had a positive RAST and 14 had a positive nasal provocation test result. On the basis of these findings and the results of the clinical examination during the peak period of pollen emission, we diagnosed chestnut pollinosis in 11 patients. We draw our conclusions from the evidence of this form of pollinosis in the Paris region, together with the reasons why it is, as yet, rarely recognized.

Changes in hepatic flow induced by continuous positive pressure ventilation in critically ill patients.

To quantify the influence of continuous positive pressure ventilation (CPPV) on hepatic plasma flow (HPF) in 8 critically ill patients submitted to controlled ventilation, we measured simultaneously HPF by the indocyanine green dye (IGD) clearance and cardiac output (CO) by the thermodilution technique, while increasing PEEP from 0--20 cm H2O. CPPV induced a significant decrease in HPF which was related to the level of PEEP. A linear correlation was documented between HPF and CO; HPF remained a constant fraction of CO during CPPV. These results suggest that the decrease in CO is the most likely mechanism of the fall in HPF during CPPV.

[Calcified constrictive pericarditis manifested by isolated hepatomegaly]. / Péricardite constrictive calcifiée relevée par une hépatomégalie isolée.

Calcified constructive pericarditis was discoverd in a 14 year old boy who presented with isolated hepatomegaly. No cause could be found. He was cured by surgery.

An autoantibody directed against human thrombin anion-binding exosite in a patient with arterial thrombosis: effects on platelets, endothelial cells, and protein C activation.

An autoantibody, developed by a patient with severe and recurrent arterial thrombosis, was characterized to be directed against the anion-binding exosite of thrombin, and inhibited all thrombin interactions requiring this secondary binding site without interfering with the catalytic site. The effect of the antibody was studied on thrombin interactions with platelets and endothelial cells from human umbilical veins (HUVEC). The autoantibody specifically and concentration-dependently inhibited alpha-thrombin-induced platelet activation and prostacyclin (PGI2) synthesis from HUVEC. It had no effect when gamma-thrombin or the thrombin receptor activation peptide SFLLR were the inducers. The effect of the antibody on protein C activation has been studied. The antibody blocked the thrombin-thrombomodulin activation of protein C. The inhibition of the activation was maximal with a low concentration of thrombomodulin. The fact that the autoantibody inhibited concentration-dependent alpha-thrombin-induced platelet and endothelial cell functions emphasizes the crucial role of the anion-binding exosite of thrombin to activate its receptor. In regard to the pathology, the antibody inhibited two vascular processes implicated in thrombin-antithrombotic functions, PGI2 secretion, and protein C activation, which could be implicated in this arterial thrombotic disease.

Winter pollinosis in Paris.

Pollen is rarely investigated as a cause of winter respiratory symptoms. Infectious coryza and asthma are particularly common during winter, and it has been shown that environmental antigens can cause at least some cases in Paris. Recent experimental data from Calhoun et al. (1991) indicate that pollen may act synergistically with viral respiratory infections, which are particularly prevalent in winter. In the present study, we investigated, in 130 consecutive patients presenting with winter aggravation of asthma or rhinitis, winter pollinosis by skin test, radioallergosorbent test (RAST), and specific endonasal challenge test. Totals of 35, 24, and 21 patients reacted positively in skin, RAST (> 0.70 PRU/ml), and endonasal tests, respectively. Clinical features during the season established the diagnosis of winter pollinosis in 20 cases; it was due to alder pollen in 10 patients and hazel pollen in 12. The positive predictive value of the skin test was only 0.57, as compared with 0.86 for the specific endonasal test, which had a negative predictive value of 1. Our results indicate that hazel and alder pollens should be prick-tested for more often as causes of winter respiratory symptoms in Paris, even if similar manifestations were absent during previous winters, were previously present during spring or summer, or were both absent in previous winters and present in spring or summer.