In vitro interactions of Acanthamoeba castellanii Neff and Vibrio harveyi.

Free-living amoebae (FLA) are opportunistic protozoa widely distributed in the environment. They are frequently found in water and soil samples, but they have also been reported to be associated with bacterial human pathogens such as Legionella spp. Campylobacter spp or Vibrio cholerae among others. Including within Vibrio spp. V. harveyi (Johnson and Shunk, 1936) is a bioluminescent marine bacteria which has been found swimming freely in tropical marine waters, being part of the stomach and intestine microflora of marine animals, and as both a primary and opportunistic pathogen of marine animals. Our aim was to study the interactions between Vibrio harveyi and Acanthamoeba castellanii Neff. Firstly, in order to analyze changes in it cultivability, V. harveyi was coincubated with A. castellanii Neff axenic culture and with Acanthamoeba Conditioned Medium (ACM) at different temperatures in aerobic conditions. Interestingly, at 4 °C and 18-20 °C bacteria were still cultivable in marine agar, at 28 °C, in aerobic conditions, but there weren't significant differences comparing with the controls. We also noted an enhanced migration of Acanthamoeba toward V. harveyi on non-nutrient agar plates compared to controls with no bacteria.

In vitro activity of 1H-phenalen-1-one derivatives against Acanthamoeba castellanii Neff and their mechanisms of cell death.

Acanthamoeba is an opportunistic pathogen which is the causal agent of a sight-threatening ulceration of the cornea known as Acanthamoeba keratitis (AK) and, more rarely, an infection of the central nervous system called "granulomatous amoebic encephalitis" (GAE). The symptoms of AK are non-specific, and so it can be misdiagnosed as a viral, bacterial, or fungal keratitis. Furthermore, current therapeutic measures against AK are arduous, and show limited efficacy against the cyst stage of Acanthamoeba. 1H-Phenalen-1-one (PH) containing compounds have been isolated from plants and fungi, where they play a crucial role in the defense mechanism of plants. Natural as well as synthetic PHs exhibit a diverse range of biological activities against fungi, protozoan parasites or human cancer cells. New synthetic PHs have been tested in this study and they show a potential activity against this protozoa.

Variation in Campylobacter jejuni culturability in presence of Acanthamoeba castellanii Neff.

Free-living amoebae (FLA) are protozoa that are widely distributed in the environment mainly in water and soil related habitats. These amoebae have also been reported to be associated with some bacterial pathogens for humans such as Campylobacter spp. The species C. jejuni is the causative agent of about 90% of human campylobacteriosis cases worldwide and this disease may even end up in severe autoimmune sequelae as Guillain-Barré syndrome (GBS). In this study, the interactions between the strain Acanthamoeba castellanii Neff and Campylobacter jejuni was investigated. Campylobacter jejuni was coincubated with Acanthamoeba castellanii Neff trophozoites at different temperatures, in order to evaluate the C. jejuni ability to grow in presence A. castellanii culture and Acanthamoeba Conditioned Medium (ACM). C. jejuni was coincubated with A. castellanii axenic culture at different temperatures in aerobic conditions. Our results revealed that bacteria were still cultivable (Blood Agar medium, at 37 °C, in microaerophilic atmosphere) after a 14 days C. jejuni - A. castellanii coculture, comparing with C. jejuni alone, which was only cultivable for 24 h.

Tricuspid valve replacement with mechanical prostheses: Short and long-term outcomes.

BACKGROUND AND AIM: Tricuspid valve replacement has been associated with high mortality and poor long-term outcomes. We report the preoperative risk factors associated with short and long-term outcomes following tricuspid valve replacement with mechanical prostheses. METHODS: In 62 patients who underwent mechanical tricuspid valve replacement, clinical, laboratory, and echocardiographic findings were analyzed using both univariate and multivariate analyses to describe operative and long-term mortality. RESULTS: In our population (mean age 59 ± 9.7 years, 82.3% female), most common causes of tricuspid valve disease were rheumatic fever (69.4%) and functional regurgitation (19.4%). Operative and long-term mortality were 17.7 and 33.9%, respectively. Age, diabetes mellitus, and coronary artery disease were independently associated with increased long-term mortality. New York Heart Association (NYHA) class and right heart failure symptoms significantly improved during follow-up. CONCLUSIONS: In this series of mechanical tricuspid valve replacements in patients with predominately rheumatic heart disease, operative and long-term mortality were increased; however, survivors had significant improvement in their NYHA class and freedom from right heart failure symptoms. Three preoperative factors (age, diabetes mellitus, and coronary artery disease) were independently associated with long-term mortality.

Prognostic value of increased carbohydrate antigen in patients with heart failure.

AIM: To study the prognostic value of carbohydrate antigen 125 (CA125) and whether it adds prognostic information to N-terminal pro-brain natriuretic peptide (NT-proBNP) in stable heart failure (HF) patients. METHODS: The predictive value of CA125 was retrospectively assessed in 156 patients with stable HF remitted to the outpatient HF unit for monitoring from 2009 to 2011. Patients were included in the study if they had a previous documented episode of HF and received HF treatment. CA125 and NT-proBNP concentrations were measured. The independent association between NT-proBNP or CA125 and mortality was assessed with Cox regression analysis, and their combined predictive ability was tested by the integrated discrimination improvement (IDI) index. RESULTS: The mean age of the 156 patients was 72 ± 12 years. During follow-up (17 ± 8 mo), 27 patients died, 1 received an urgent heart transplantation and 106 required hospitalization for HF. Higher CA125 values were correlated with outcomes: 58 ± 85 KU/L if hospitalized vs 34 ± 61 KU/L if not (P < 0.05), and 94 ± 121 KU/L in those who died or needed urgent heart transplantation vs 45 ± 78 KU/L in survivors (P < 0.01). After adjusting for propensity scores, the highest risk was observed when both biomarkers were elevated vs not elevated (HR = 8.95, 95%CI: 3.11-25.73; P < 0.001) and intermediate when only NT-proBNP was elevated vs not elevated (HR = 4.15, 95%CI: 1.41-12.24; P < 0.01). Moreover, when CA125 was added to the clinical model with NT-proBNP, a 4% (P < 0.05) improvement in the IDI was found. CONCLUSION: CA125 > 60 KU/L identified patients in stable HF with poor survival. Circulating CA125 level adds prognostic value to NT-proBNP level in predicting HF outcomes.

Long term outcome of mechanical valve prosthesis in the pulmonary position.

OBJECTIVES: Assessment of the long term outcome of mechanical valve prosthesis at pulmonary position in a population of grown-up congenital heart disease patients from a tertiary referral center. METHODS: From 1977 to 2007, 22 consecutive patients underwent a total of 25 pulmonary valve replacements with mechanical prosthesis. The most frequent underlying cardiac condition was tetralogy of Fallot (n=16, 64%) and the mean age at the time of pulmonary valve replacement was 32 ± 11 years (range 14-50 years). RESULTS: The postoperative mortality rate was 4% (n=1) with no late deaths documented after a mean follow-up of 7.6 ± 7.6 years (range 0.29-24 years). No major bleeding episodes occurred. Three patients presented with valve thrombosis in the setting of long term anticoagulation withdrawal and required valve re-replacement. Two of these patients, both with poor right ventricular function and overt clinical signs of right heart failure at the time of valve re-replacement, experienced further episodes of thrombosis despite correct anticoagulation. All episodes resolved with thrombolysis. After addition of antiplatelet treatment in one case and anticoagulation self-control, in the other, no further thrombosis has been documented. CONCLUSIONS: Mechanical valve prosthesis may be an alternative to tissue valve prosthesis in patients with congenital heart disease requiring pulmonary valve replacement. Optimal anticoagulation is crucial and additional antiplatelet treatment should be considered. Our data also suggest that patients with severe right ventricular dysfunction and congestive heart failure might be at particular risk for valve thrombosis.