Consecutive episodes of heart and kidney failure in an "otherwise" healthy young man.

BACKGROUND: Acute renal failure is a rare occurrence in a patient with an unremarkable past medical history and should always lead to an in depth clinical study. The occurrence in the same healthy young subject, of consecutive episodes of heart failure and of acute renal failure is an even rarer event and should prompt diagnostic tests and restrict the diagnostic hypotheses. CASE PRESENTATION: We present the case of a 28 year-old man who, while waiting to undergo assessment for a mild chronic kidney disease, was diagnosed with decompensated dilated cardiomyopathy and placed on diuretics and ß-blockers. After few weeks he developed a non oligoanuric acute renal failure with a slight elevation of serum calcium. Renal biopsy proved suggestive for renal sarcoidosis; thus the hypothesis of systemic sarcoidosis with cardiac and renal involvement was possible avoiding further delay in initiation of therapy. CONCLUSIONS: Cardiac sarcoidosis is usually silent but the majority of cases are diagnosed when cardiac symptoms are present in a patient with systemic sarcoidosis. Renal involvement with granulomatous interstitial nephritis is also quite rare and can be an unexpected finding at kidney biopsy. This case highlights the need to evaluate thoroughly clinical problems that do not fit in a specific scenario and emphasizes the importance of performing a kidney biopsy in case of kidney failure of unknown etiology.

[Improving vaccination social marketing by monitoring the web]. / Migliorare il marketing sociale in tema di vaccinazioni "presidiando" il Web.

Immunisation is one of the most important and cost- effective interventions in Public Health because of their significant positive impact on population health.However, since Jenner's discovery there always been a lively debate between supporters and opponents of vaccination; Today the antivaccination movement spreads its message mostly on the web, disseminating inaccurate data through blogs and forums, increasing vaccine rejection.In this context, the Società Italiana di Igiene (SItI) created a web project in order to fight the misinformation on the web regarding vaccinations, through a series of information tools, including scientific articles, educational information, video and multimedia presentations The web portal (http://www.vaccinarsi.org) was published in May 2013 and now is already available over one hundred web pages related to vaccinations Recently a Forum, a periodic newsletter and a Twitter page have been created. There has been an average of 10,000 hits per month. Currently our users are mostly healthcare professionals. The visibility of the site is very good and it currently ranks first in the Google's search engine, taping the word "vaccinarsi" The results of the first four months of activity are extremely encouraging and show the importance of this project; furthermore the application for quality certification by independent international Organizations has been submitted.

Case Report: An unusual case of a transposition of the great arteries with a double aortic arch: a highly complex fetal diagnosis with an unpredictable outcome.

Published data estimate the prevalence of the vascular ring at approximately 7 per 10,000 live births. The association of a double aortic arch with a D-transposition of the great arteries has been rarely described in the literature. In this study, we report the prenatal diagnosis of a 28-year-old woman. A fetal echocardiography at a gestational age of 24 weeks + 6 days showed a D-transposition of the great arteries and a double aortic arch with a ventricular septal defect and pulmonary stenosis. On the first night after birth, the baby experienced an increase in lactate levels, with the rate of oxygen saturation consistently below 80%. A few hours after birth, the patient underwent a Rashkind procedure. An echocardiography, CT chest x-ray, and CT angiogram confirmed a diagnosis with a severe reduction of the tracheal lumen (>85%) and bronchomalacia. Then, the patient underwent posterior tracheopexy and aortopexy and later an arterial switch operation, ventricular septal defect closure, and resection of a part of the infundibular septum, accepting the risk of potential neoaortic obstruction. The literature has reported only two cases of patients with a fetal echocardiogram diagnosis. Therefore, our patient is only the third one with a fetal diagnosis and the second one with a complex intracardiac anatomy, characterized not only by a ventricular septal defect but also by two separate components of the obstruction (a bicuspid valve and a dysplastic valve with a posterior deviation of the infundibular septum). In conclusion, a D-transposition of the great arteries with a double aortic arch remains an extremely unusual association. The clinical outcome of these patients presents a high degree of variability and is entirely unpredictable in prenatal life. Our greatest aim as fetal and perinatal cardiologists is to improve the management and outcome of these patients through a fetal diagnosis, recognizing types of congenital heart disease in newborns who require early neonatal invasive procedures.

RadioLab project: knowledge of radon gas in Italy.

RadioLab is an Italian project, addressed to school-age people, and designed for the dissemination of scientific culture on the theme of environmental radioactivity, with particular regards to the importance of knowledge of radon gas exposure. The project is a nationwide initiative promoted by the National Institute of Nuclear Physics- INFN. First tool used by the project, and of immediate impact to assess the public awareness on radon, is the administration of the survey "do you know the radon gas?". In the survey, together with the knowledge of radon and of its sources, information on personal, cultural and territorial details regarding the interviewees are also taken. Reasonably, the survey invests not only young people, but also their relatives, school workers and, gradually, the public. The survey is administrated during exhibitions or outreach events devoted to schools, but also open to the public. The survey is in dual form: printed and online. The online mode clearly leads RadioLab project even outside the school environment. Based on the results of the survey, several statistical analyses have been performed and many conclusions are drawn about the knowledge of the population on the radon risk. The RadioLab benefit and the requirement to carry on the project goals, spreading awareness of environmental radioactivity from radon, emerge. The dataset involves all twenty Italian regions and consists of 28,612 entries covering the 5-year period 2018-2022.

Swimming pools and health-related behaviours: results of an Italian multicentre study on showering habits among pool users.

OBJECTIVES: Showering before entering a swimming pool is highly recommended to reduce the risk of biological and chemical contamination. This study evaluated the behaviour of indoor swimming pool users; analysed the variables associated with lack of showering; and assessed awareness of the importance of showering. STUDY DESIGN: Cross-sectional study. METHODS: A self-administered questionnaire was used to collect data about users of swimming pools located in five different Italian cities. The association between specific variables and the lack of showering was assessed. P < 0.05 was considered to indicate statistical significance. RESULTS: In total, 4356 questionnaires were analysed. Sixty-five percent of interviewees always showered before entering the pool. The main reason given for pre-swim showering was 'to wash oneself' (50.5%); or 'to get used to the temperature of the water' (44.3%); and 5.2% answered 'for both reasons'. Risk factors significantly associated with lack of showering were: female sex (odds ratio (OR) 1.37, 95% confidence interval (CI) 1.2-1.59), age 14-17 years (OR 5.09, 95% CI 3.40-7.64); not reading the swimming pool rules (OR 1.24, 95% CI 1.10-1.41); living in Central Italy (OR 3.3, 95% CI 2.65-4.1) or Southern Italy (OR 1.35, 95% CI 1.18-1.55); and previous/current attendance of a swimming course (OR 1.7, 95% CI 1.48-1.97). CONCLUSIONS: The results revealed low compliance with the rule of showering before entering a swimming pool, and little awareness of the preventive role of showering in the hygienic management of swimming pools. There is a need for targeted educational interventions to inform swimming pool users of the reasons for the importance of showering before entering a pool.

High hydrostatic pressure activity on the disinfection of clams artificially contaminated with feline calicivirus.

BACKGROUND: The contamination of shellfish with gastroenteric viruses may cause outbreaks because they are often eaten raw or under-cooked. High-hydrostatic pressure treatments have already proven to be effective in reducing high viral load in shellfish samples. The objectives are the assessment of the viral load reduction of contaminated clams using HHP treatments at different pressures and times and the study of the changes caused by these treatments in some food physical parameters. METHODS: Clams were contaminated with a solution containing Feline Calicivirus; they were closed in envelopes and treated with 300, 400, 500, 600 MPa for 1, 3, 5, 7 min for every pressure value. After the treatment the residual viral titre was calculated. The texture parameters were obtained after treating clams samples at the same pressure values but only for 3 and 7 min and analysing them with a TPA test. RESULTS: HHP treatments of 500 and 600 MPa were sufficient to cause a total inactivation at every timelength considered while with 300 and 400 MPa after 1 min, concentrations of 1.13 and 0.55 respectively were found. In general hardness and gumminess tend to increase after the treatment whereas springiness and cohesiveness decrease a bit. CONCLUSIONS: HHP treatments showed good sterilization ability against FCV but it's necessary to consider that FCV has a lower resistance to disinfection than Human norovirus. Texture changes are in line with what is reported in literature.

Immunity status against poliomyelitis in childbearing women in a province of northern Italy. A cross-sectional analysis.

This cross-sectional seroprevalence study was carried out in 2007 to estimate the immunological status associated with poliomyelitis among fertile women , according to demographic changes. We consecutively enrolled 493 healthy mothers at the time of delivery in order to assess immunity against poliomyelitis by a neutralisation inhibition test. Despite the lack of seronegative subjects, our investigation showed low GMTs, which confirmed a reduction in the "booster effect". The GMTs against poliovirus 1, poliovirus 2 and poliovirus 3 were 25.20, 14.79 and 8.80, respectively. The data that emerged from our survey showed that GMTs have decreased significantly since 1983 and reached low-to-medium values over the past 25 years. The serum prevalence studies, together with the vaccination coverage estimates, are useful and are strongly recommended in order to highlight and identify the possible scenarios in which susceptible subject groups may be present simultaneously as well the possibility of the reintroduction of wild virus in an area that was previously free of polio.

Impact of cane use on pain, function, general health and energy expenditure during gait in patients with knee osteoarthritis: a randomised controlled trial.

OBJECTIVE: To assess the impact of daily cane use during gait in relation to pain, function, general health and energy expenditure among patients with knee osteoarthritis. METHOD: Sixty-four patients were randomly assigned to an experimental group (EG) or control group (CG). The EG used a cane every day for 2 months, whereas the CG did not use a cane in this period. The first outcome was pain and the second were function (Lequesne and WOMAC), general health (SF-36) and energy expenditure (gas analysis during the 6-minute walk test (6MWT) with and without a cane). Evaluations were performed at baseline, 30 and 60 days. RESULTS: The groups were homogeneous for all parameters at baseline. Compared with the CG, the EG significantly improved pain (ES 0.18), function - Lequesne (ES 0.13), some domains of SF-36 (role physical, ES 0.07 and bodily pain, ES 0.08) and distance on the 6MWT with the cane (ES 0.16). At the end of the 6MWT with the cane, the EG significantly improved energy expenditure (ES 0.21), carbon dioxide production (ES 0.12) and metabolic equivalents (ES 0.15) compared with the CG. CONCLUSION: A cane can be used to diminish pain, improve function and some aspects of quality of life in patients with knee osteoarthritis. The prescription of a cane should take into account the substantial increase in energy expenditure in the first month of use, whereas energy expenditure is no longer a factor for concern by the end of the second month due to adaptation to cane use. The trial was registered in clinicaltrials.gov (NCT00698412).

Factors associated with access to antiviral treatment in a multicentre cross-sectional study of patients with chronic hepatitis B in Italy.

A multicentre cross-sectional survey was performed to provide an accurate picture of patients with chronic hepatitis B (CHB) cared for by Italian Infectious Diseases Centers (IDCs). This analysis describes factors associated with access to the treatment of CHB in a country where barriers to treatment are not expected to exist because of comprehensive coverage under the National Health System (NHS). The study was performed in 74 IDCs. The analysis focused on 3305 patients with CHB of 3760 HBsAg-positive patients enrolled from March to September, 2008. To account for missing values, a Multiple Imputation method was used. Treatment was reported in 2091 (63.3%) patients. In the multivariate analysis, an increased chance of getting treatment was independently associated with 10 years increase of age at diagnosis (adjusted odds ratio [aOR] 1.2, 95% confidence interval [CI] 1.1-1.3, P < 0.001), HBeAg positivity (aOR 1.8, 95% CI 1.1-2.8, P < 0.001), cirrhosis (aOR 3.6, 95% CI 2-6.3, P = 0.012), HDV (aOR 1.6, 95% CI 1.02-2.5, P = 0.042) and HIV positivity (aOR 6.5, 95% CI 4-10.8, P < 0.001). Conversely, a decreased chance was associated with female gender (aOR 0.6, 95% CI 0.5-0.7, P < 0.001), immigration (aOR 0.6, 95% CI 0.5-0.9, P = 0.009), alcohol consumption (aOR 0.7, 95% CI 0.5-0.98, P = 0.04) and HCV positivity (aOR 0.5, 95% CI 0.3-0.8, P = 0.005). Our study shows that Italian IDCs treat a high percentage of patients with CHB. Nevertheless, disparities exist which are not related to the severity of disease limiting access to antiviral therapy of CHB, even in a country with a universal healthcare system.

Inhaled ammonium persulphate inhibits non-adrenergic, non-cholinergic relaxations in the guinea pig isolated trachea.

BACKGROUND: Persulphates can act both as irritants and sensitizers in inducing occupational asthma. A dysfunction of nervous control regulating the airway tone has been hypothesized as a mechanism underlying bronchoconstriction in asthma. OBJECTIVES: It was the aim of this study to investigate whether inhaled ammonium persulphate affects the non-adrenergic, non-cholinergic (NANC) inhibitory innervation, the cholinergic nerve-mediated contraction or the muscular response to the spasmogens, carbachol or histamine, in the guinea pig epithelium-free, isolated trachea. METHODS: Male guinea pigs inhaled aerosols containing ammonium persulphate (10 mg/m(3) for 30 min for 5 days during 3 weeks). Control animals inhaled saline aerosol. NANC relaxations to electrical field stimulation at 3 Hz were evaluated in whole tracheal segments as intraluminal pressure changes. Drugs inactivating peptide transmission, nitric oxide synthase, carbon monoxide production by haem oxygenase-2 and soluble guanylyl cyclase were used to assess the involvement of various inhibitory neurotransmitters. Carbachol and histamine cumulative concentration-response curves were obtained. RESULTS: In both groups, nitric oxide and carbon monoxide participated to the same extent as inhibitory neurotransmitters. In exposed animals, the tracheal NANC relaxations were reduced to 45.9 +/- 12.1% (p < 0.01). The cholinergic nerve-mediated contractions to electrical field stimulation and the muscular response to histamine were not modified by ammonium persulphate exposure. The muscular response to carbachol was unaffected up to 1 microM. Conversely, the response to the maximal concentration of carbachol (3 microM) was increased (p < 0.01). CONCLUSION: Ammonium persulphate inhalation at high concentrations impairs the nervous NANC inhibitory control in the guinea pig airways. This may represent a novel mechanism contributing to persulphate-induced asthma.

Detection of enteroviruses from urban sewage in Parma.

BACKGROUND AND AIM OF THE WORK: The human enteroviruses (EV) are the most common and widespread human viruses in the world. They have bowel as their natural habitat and they can spread in the environment through the faecal excretion. In the continental climate Regions these viruses may cause epidemic outbreaks in summer and fall, while in the tropical Regions the EV infections present a high incidence during all year. The symptoms can be minor or subclinic, but they can be also associated to rare and serious diseases. The aim of this study was to evaluate the environmental circulation of polioviruses and non-polio enteroviruses (NPEV) using standard methods of urban wastewater surveillance recommended by the WHO. METHODS: A total of 188 wastewater samples were collected between February 2005 and December 2008 from two sewage treatment plants in Parma. The sampling was carried out twice a month. Environmental variables were collected for each day of sampling. RESULTS: Out of the 188 examined wastewater samples, 78.7% were positive to the enterovirus research. One out of the 148 positive samples was identified as poliovirus Sabin-like type 3. The remaining 147 positive samples were enteroviruses non polio: Coxsakieviruses and Echoviruses. All Coxsakieviruses isolated were of type B. CONCLUSIONS: The proposed method has shown high sensibility, also in presence of very low expected prevalence of vaccine poliovirus. It allows to verify the kind and relative frequency of enteric viruses circulating in the country, whose characteristics (virulence and pathogenicity) may vary with reference to a different epidemiologic and demographic structure of the resident population.

[Hospital admission of subjects with chronic obstructive bronchopulmonary disease (COPD) and air pollution in the city of Parma (Italy). A preliminary analysis]. / Funzionalità respiratoria in soggetti con Broncopneumopatia Cronica Ostruttiva (BPCO) e inquinamento atmosferico nella città di Parma Analisi preliminare.

A study was conducted in subjects admitted to hospital for chronic obstructive bronchopulmonary disease (COPD) in the city of Parma (Italy). The aim was to evaluate changes in patients' percent vital capacity (VC), forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), as a function of changing degrees of atmospheric pollution as measured by PM10, NO2 and O3 concentrations in the outside air. Study results revealed an association between PM10 concentrations and hospital admissions for COPD. Statistically significant differences were found between PM10 concentrations measured three-four days before admission and in days not followed by admission to hospital. Regression analysis between PM10 concentrations at 24, 48, 72, and 96 hours before admission and respiratory function showed a significant association between FVC% and FEV1% and PM10 concentrations at 96 hours. The relative risk was calculated to be 1.016 (95% confidence intervals: 1.001-1.032), which corresponds to a 1.6% increased risk of admission to hospital for COPD for each unit increase in PM10 concentration in the outside air.

Comprehensive exercise training improves ventilatory muscle function and reduces dyspnea perception in patients with COPD.

BACKGROUND: Comprehensive exercise training (CET) is an efficient strategy to decrease dyspnea perception in chronic obstructive pulmonary disease (COPD) and may result in significant improvement in ventilatory muscles function. Our aim was to evaluate the effects of general exercise training on dyspnea perception and on respiratory muscles strength in COPD patients. METHODS: Consecutive COPD patients were enrolled to complete a CET programme. The patients underwent a routine that included a global warm up, upper and lower limbs endurance exercise as well as stretching and relaxation. Before and after the CET programme, patients completed maximal inspiratory (PImax) and expiratory (PEmax) pressures measurements, maximal incremental test, endurance test, and 6-min walk distance (6MWD). RESULTS: 71 patients (52 male). Mean age 67.6 +/- 8.6 years, FEV1 (%) 44.2 +/- 16.2 and Mahler dyspnea scale 6.4 +/- 1.8. The results before and after the exercise programme were: PImax 64.7 +/- 22.9 vs. 75.5 +/- 23.7 cmH2O (p=0.001), PEmax 110.8 +/- 28.1 vs. 120.4 +/- 28.1 cmH2O (p=0.004), 6MWD 510.6 +/- 90.3 vs. 528.2 +/- 99.7 metres (p=0.88), time of incremental test 672 +/- 135 vs. 856 +/- 226 sec (p<0.0001). Compared with the pre exercise programme, we observed a significant reduction on Borg dyspnea scale (6.1 +/- 2.8 to 3.6 +/- 2.3, p<0.0001) as well as a longer test time (504 +/- 218 to 1.038 +/- 841, p<0.0001) at the end of the endurance test after CET programme. Improvement of PImax correlated negatively with dyspnea perception at iso-time during the endurance test (r = -0.33, p=0.03). CONCLUSIONS: Our results confirm that CET is associated with significant improvement in PImax, PEmax and provide evidence demonstrating that CET reduces dyspnea perception in patients with COPD.

Genetic analysis of human and swine influenza A viruses isolated in Northern Italy during 2010-2015.

Influenza A virus (IAV) infection in swine plays an important role in the ecology of influenza viruses. The emergence of new IAVs comes through different mechanisms, with the genetic reassortment of genes between influenza viruses, also originating from different species, being common. We performed a genetic analysis on 179 IAV isolates from humans (n. 75) and pigs (n. 104) collected in Northern Italy between 2010 and 2015, to monitor the genetic exchange between human and swine IAVs. No cases of human infection with swine strains were noticed, but direct infections of swine with H1N1pdm09 strains were detected. Moreover, we pointed out a continuous circulation of H1N1pdm09 strains in swine populations evidenced by the introduction of internal genes of this subtype. These events contribute to generating new viral variants-possibly endowed with pandemic potential-and emphasize the importance of continuous surveillance at both animal and human level.

Influence of protein C activation on blood coagulation and fibrinolysis in squirrel monkeys.

Protein C is a circulating proenzyme which, upon activation, exerts a potent anticoagulant activity. Infusion of activated bovine protein C into dogs is accompanied by an increase of circulating tissue plasminogen activator (PA) activity. However, the evidence that human protein C shares a similar profibrinolytic capacity is still lacking. Therefore, we investigated the profibrinolytic properties of human protein C in squirrel monkeys (Samiri sciureus). Injection of activated human protein C resulted in prolongation of the activated partial thromboplastin time but was not associated with increased fibrinolytic activity of blood. Similarly, activation of endogenous protein C (up to 20-30%) by infusion of thrombin-thrombomodulin complex markedly reduced blood coagulability without being accompanied by an increase of circulating PA activity. The in vivo-generated anticoagulant activity was identified as activated protein C by the following observations. It was neutralized by rabbit anti-human protein C-IgG, was slowly inhibited by plasma but not by anti-thrombin III, was adsorbable on barium citrate, and expressed amidolytic activity. Activation of protein C appeared to be selective since other parameters such as thrombin time, platelet count, fibrinogen, and factor V levels were unaffected by thrombin-thrombomodulin infusion. Infusion of human plasma derived from whole blood incubated in vitro with human activated protein C also did not induce a fibrinolytic response, suggesting that no second messengers with PA-releasing activity were being generated in blood. It is concluded that in a primate, neither the administration of activated human protein C nor the activation of endogenous protein C are associated with an increase of fibrinolytic activity. These findings question the role of this enzyme in the regulation of PA release in man.

Generation in plasma of a fast-acting inhibitor of plasminogen activator in response to endotoxin stimulation.

Endotoxin producing bacteria cause disseminated intravascular coagulation (DIC); however, the mechanism of endotoxin action in man is still unclear. Impairment of the fibrinolytic system has been suggested as a contributing mechanism. A single injection of Escherichia coli lipopolysaccharide in rabbits resulted in a marked and prolonged increase of the levels of a fast-acting inhibitor of plasminogen activator (PA-inhibitor) in plasma (from 3.9 +/- 0.7 to 41 +/- 13.2 U/ml after 3 h). Gel filtration studies indicated that inhibition of human tissue-type plasminogen activator (t-PA) by rabbit plasma is accompanied by a change in the elution profile of the activator compatible with the formation of an enzyme-inhibitor complex with an apparent molecular weight of 100,000. Injection of human t-PA (1,500 IU/kg body wt) in endotoxin treated animals resulted in very fast inhibition of t-PA and formation of a similar complex. The half-life of circulating PA-inhibitor activity in rabbits was about 7 min as estimated by donor receiver plasma transfusion experiments. Stimulation of cultured human endothelial cells with endotoxin resulted in enhanced rate of accumulation of PA-inhibitor activity in the culture medium (two- to sevenfold increase). In five patients with septicemia, markedly increased levels of PA-inhibitor (14.3 +/- 15.5 U/ml) as compared with control subjects (1.3 +/- 0.7 U/ml) were observed in plasma. A very strong correlation (r = 0.98) was found between inhibition of t-PA and of urokinase in all conditions, suggesting that this fast-acting inhibitor reacts with both plasminogen activators. These data suggest that the appearance of this fast-acting PA-inhibitor is very sensitive to endotoxin stimulation. The marked increase in the level of PA-inhibitor in blood may contribute to the pathogenesis of DIC in septicemia.

Influence of the fast-acting inhibitor of plasminogen activator on in vivo thrombolysis induced by tissue-type plasminogen activator in rabbits. Interference of tissue-derived components.

The influence of endotoxin-induced elevated plasma levels of the fast-acting inhibitor of plasminogen activator (PA-inhibitor) on thrombolysis was investigated in rabbits with a jugular vein thrombus. Infusion of human tissue-type plasminogen activator (t-PA) produced similar degrees of thrombolysis in control and endotoxin-treated rabbits, although no free t-PA could be demonstrated in plasma of endotoxin-treated animals. Infusion of t-PA in an extracorporeal arteriovenous shunt resulted in loss of thrombolytic activity in endotoxin-treated animals but not in control animals. Blood clots superfused in vitro with mixtures of t-PA and normal plasma lysed in contrast to clots superfused with t-PA and PA-inhibitor-rich plasma. However, addition of rabbit lung slices to the plasma surrounding the blood clot, reversed the inhibition of thrombolysis by PA-inhibitor-rich plasma. This indicates that tissue-derived factor(s) are involved in the regulation of in vivo thrombolysis. These hypothetical factor(s) are, however, very unstable in plasma, which has thus far precluded their further characterization.

Cultured human endothelial cells generate tissue factor in response to endotoxin.

Bacterial infection is associated with disseminated intravascular coagulation and fibrin deposition in the microcirculation; the mechanism of these effects in humans is still unclear. We have studied the generation of procoagulant activity (PCA) by cultured human endothelial cells (EC) in response to endotoxin. Cells from umbilical cord veins were grown in Eagle's minimum essential medium with 20% fetal calf serum till confluence. Absence of fibroblasts and macrophages was carefully checked. Endotoxin (Salmonella enteritidis lipopolysaccharide (LPS) W or Escherichia coli 0111:B4 LPS W, 0.01-1.0 micrograms/ml) was added to culture dishes for 4-6 h. PCA of EC was measured by a one-stage clotting assay and/or a two-stage amidolytic assay with the chromogenic substrate S-2222. In the absence of endotoxin, EC generated little, if any PCA (2-5 units/10(5) cells). In contrast, the addition of endotoxin resulted in generation of strong PCA that reached a maximum within 4-6 h (185-241 units/10(5) cells) and was dose-dependent between 1 and 0.01 microgram endotoxin/ml of culture medium. The generation of PCA required RNA and protein synthesis but did not require the presence of serum. No activity was found in the culture medium. The activity was of tissue thromboplastin type, as indicated by biological and immunological criteria. These endotoxin effects were observed in the absence of endothelial damage, as shown by phase-contrast microscopy and lack of 51Cr release. These data could contribute to elucidate the pathogenesis of vascular complications associated with endotoxemia in man.

Activated human protein C prevents thrombin-induced thromboembolism in mice. Evidence that activated protein c reduces intravascular fibrin accumulation through the inhibition of additional thrombin generation.

Activated protein C (APC) is a potent physiologic anticoagulant with profibrinolytic properties, and has been shown to prevent thrombosis in different experimental models. We investigated the effect of human APC on thrombin-induced thromboembolism in mice, a model of acute intravascular fibrin deposition leading to death within minutes. APC given intravenously (i.v.) as a bolus 2 min before thrombin challenge (1,250 U/kg) reduced mortality in a dose-dependent manner despite the lack of thrombin inhibitor activity. Significant inhibition of thrombin-induced death was observed at the dose of 0.05 mg/kg, and maximal protection was obtained with 2 mg/kg (> 85% reduction in mortality rate). Histology of lung tissue revealed that APC treatment (2 mg/kg) reduced significantly vascular occlusion rate (from 89.2 to 46.6%, P < 0.01). The protective effect of APC was due to the inhibition of endogenous thrombin formation as indicated by the fact that (a) the injection of human thrombin caused a marked decrease in the coagulation factors of the intrinsic and common pathways (but not of Factor VII), suggesting the activation of blood clotting via the contact system; (b) APC pretreatment reduced markedly prothrombin consumption; (c) the lethal effect of thrombin was almost abolished when the animals were made deficient in vitamin K-dependent factors by warfarin treatment, and could be restored only by doubling the dose of thrombin, indicating that the generation of endogenous thrombin contributes significantly to death; and (d) APC failed to protect warfarin-treated animals, in which mortality is entirely due to injected thrombin, even after protein S supplementation. Other results suggest that APC protects from thrombin-induced thromboembolism by rendering the formed fibrin more susceptible to plasmin degradation rather than by reducing fibrin formation: in thrombin-treated mice, fibrinogen consumption was not inhibited by APC; and inhibition of endogenous fibrinolysis by epsilon-aminocaproic or tranexamic acid resulted in a significant reduction of the protective effect of APC. Since APC did not enhance plasma fibrinolytic activity, as assessed by the measurement of plasminogen activator (PA) or PA inhibitor (PAI) activities, PAI-1 antigen, or 125I-fibrin degrading activity, we speculate that the inhibition of additional (endogenous) thrombin formation by APC interrupts thrombin-dependent mechanisms that make fibrin clots more resistant to lysis, so that the intravascular deposited fibrin can be removed more rapidly by the endogenous fibrinolytic system.