Temperature-induced zeaxanthin overproduction in Synechococcus elongatus PCC 7942.

The exogenous crtZ gene from Brevundimonas sp. SD212, coding for a 3,3' ß-car hydroxylase, was expressed in Synechococcus elongatus PCC 7942 under the control of a temperature-inducible promoter in an attempt to engineer the carotenoid metabolic pathway, to increase the content of zeaxanthin and its further hydroxylated derivatives caloxanthin and nostoxanthin. These molecules are of particular interest due to their renowned antioxidant properties. Cultivation of the engineered strain S7942Z-Ti at 35 °C, a temperature which is well tolerated by the wild-type strain and at which the inducible expression system is activated, led to a significant redistribution of the relative carotenoid content. ß-Carotene decreased to about 10% of the pool that is an excess of a threefold decrease with respect to the control, and concomitantly, zeaxanthin became the dominant carotenoid accounting for about half of the pool. As a consequence, zeaxanthin and its derivatives caloxanthin and nostoxanthin collectively accounted for about 90% of the accumulated carotenoids. Yet, upon induction of CrtZ expression at 35 °C the S7942Z-Ti strain displayed a substantial growth impairment accompanied, initially, by a relative loss of carotenoids and successively by the appearance of chlorophyll degradation products which can be interpreted as markers of cellular stress. These observations suggest a limit to the exploitation of Synechococcus elongatus PCC 7942 for biotechnological purposes aimed at increasing the production of hydroxylated carotenoids.

Sharp Transition in the Lift Force of a Fluid Flowing Past Nonsymmetrical Obstacles: Evidence for a Lift Crisis in the Drag Crisis Regime.

Bluff bodies moving in a fluid experience a drag force which usually increases with velocity. However in a particular velocity range a drag crisis is observed, i.e., a sharp and strong decrease of the drag force. This counterintuitive result is well characterized for a sphere or a cylinder. Here we show that, for an object breaking the up-down symmetry, a lift crisis is observed simultaneously to the drag crisis. The term lift crisis refers to the fact that at constant incidence the time-averaged transverse force, which remains small or even negative at low velocity, transitions abruptly to large positive values above a critical flow velocity. This transition is characterized from direct force measurements as well as from change in the velocity field around the obstacle.

Novel Key Ingredients in Urinary Tract Health-The Role of D-mannose, Chondroitin Sulphate, Hyaluronic Acid, and N-acetylcysteine in Urinary Tract Infections (Uroial PLUS®).

Urinary tract infections represent a common and significant health concern worldwide. The high rate of recurrence and the increasing antibiotic resistance of uropathogens are further worsening the current scenario. Nevertheless, novel key ingredients such as D-mannose, chondroitin sulphate, hyaluronic acid, and N-acetylcysteine could represent an important alternative or adjuvant to the prevention and treatment strategies of urinary tract infections. Several studies have indeed evaluated the efficacy and the potential use of these compounds in urinary tract health. In this review, we aimed to summarize the characteristics, the role, and the application of the previously reported compounds, alone and in combination, in urinary tract health, focusing on their potential role in urinary tract infections.

Risk for contrast nephropathy in patients undergoing coronarography.

Among the causes of in-hospital acute renal failure, contrast-induced nephropathy ranks third in prevalence. Although it represents a condition of renal impairment with spontaneous recovery, contrast nephropathy should always be considered, because it prolongs hospitalization and it may become a severe complication requiring dialysis. The purposes of this study are: (i) to determine if the application of the most effective contrast-induced nephropathy prevention strategies in the Cardiology Intensive Care Unit can prove to be successful in reducing nephropathy risk; and (ii) to identify which of the involved risk factors persist after the preventive treatment. We examined the patients who had a coronarography at the Bentivoglio hospital from April 2007 to April 2008 who required at least 3 days of permanence in hospital due to the presence of potential risk factors; 136 out of 784 patients were included. Among the selected patients, 21 (15.44%) developed a renal impairment compatible with contrast-induced nephropathy. The risk factors that seemed to display the best correlation with risk of contrast nephropathy were advanced age and an ventricular failure (ejection fraction <40%); however, the critical condition did not appear to be due to a single risk factor, but it resulted from the association of more contextual risk factors. Particularly, the concomitant presence of ventricular failure, anemia, diabetes, previous myocardial infarction and advanced age (>70 years) determined a threefold increased risk of contrast nephropathy. Our data suggest that the development of contrast nephropathy following coronarography is associated with worse renal function during hospitalization and at discharge.

Post-coronarography application of continuous veno-venous hemofiltration in the prevention of contrast nephropathy in patients with complex multisystem deficiency.

BACKGROUND: An increased admission of high-risk patients to diagnostic and interventional radiological procedures with contrast medium has resulted in an increase of contrast-induced nephropathy, which now represents the third main cause of hospital-acquired acute renal failure. The pathogenic mechanism of contrast-induced nephropathy (CN) is unclear, but there is much evidence which indicated an interaction between direct tubular cytotoxicity and osmotic/hemodynamic effects. Continuous veno-venous hemofiltration (CVVH) has shown possible benefits in preventing CN. It is not understood when and how prophylactic strategies should be used either in pharmacological therapies or in continous renal replacement therapy (CRRT) approaches. The aim of this study was to evaluate the efficiency of the CVVH technique in preventing CN secondary to emergency radiological procedures in very high-risk patients. PATIENTS AND METHODS: Twelve patients with severe chronic renal impairment (serum creatinine concentration >2 mg/dl with an estimated glomerular filtration rate (eGFR) <40 ml/min) in association with at least two severe comorbidities (such as previous acute myocardial infarction in hypertensive or diabetic patients obesity, cardiac failure with ejection fraction <40%, severe hypotension) were treated with CVVH after coronarography using an iso-osmolar contrast medium (Visipaque, Iodixanol), with or without percutaneous transluminal coronary angioplasty. Adverse events and their association with the interventional radiological procedure were investigated after hemofiltration. RESULTS: Statistically significant differences were observed for both eGFR and serum creatinine at different time points (pre-, post- and 7 days after the procedure) at p<0.05. Statistical analysis of all the variables related to the radiological procedure and the hemofiltration technique did not cause any modification of renal function between the pre- and post-procedure values. No patient showed signs of cardiovascular instability, nor were any episodes of marked hypotension reported during the dialysis session. No patient showed any adverse effects related to the interventional radiological procedure or to the CVVH technique. Renal function, according to serum creatinine concentration and the e-GFR calculation (Cockcroft), did not worsen but had improved when the patients left hospital, with function rates statistically significantly better compared to that on hospital admission, even 7 days after the radiological procedure. CONCLUSION: The present study suggests the efficiency of the CVVH technique in preventing CN in high-risk patients who need to undergo interventional radiological cardiovascular procedures involving the administration of an iodine-based contrast medium.

Effect of Abciximab on prothrombin activation and thrombin generation in acute coronary syndromes without ST-segment elevation: Global Utilization of Strategies to Open Occluded Coronary Arteries Trial IV in Acute Coronary Syndromes (GUSTO IV ACS) Italian Hematologic Substudy.

BACKGROUND: Abciximab is very effective in reducing major cardiac events in patients undergoing interventional procedures. Its antithrombotic effect is primarily attributable to the blocking of platelet glycoprotein IIb/IIIa receptors, but recent evidence suggests that it may have a direct antithrombin effect. No data are available concerning the effect of abciximab on the in vivo markers of prothrombin activation and thrombin generation in patients with acute coronary syndromes without ST elevation. METHODS AND RESULTS: We measured the plasma levels of prothrombin fragment 1+2 (a marker of prothrombin activation) and the thrombin/antithrombin complex (a marker of thrombin generation) in 167 patients with acute coronary syndromes without ST elevation enrolled in the GUSTO IV ACS trial who were randomized to receive abciximab for 24 hours (52 patients), abciximab for 48 hours (59 patients), or placebo (56 patients) in addition to heparin. Blood samples were obtained at baseline (before any treatment), after 24 and 48 hours (before study drug discontinuation), and 1 month later. There was a significant increase in the plasma levels of prothrombin fragment 1+2 after 48 hours and after 1 month in all 3 groups, placebo (P=0.0001), 24-hour abciximab (P=0.0002), and 48-hour abciximab (P=0.0001). The plasma thrombin/antithrombin complex levels were similar in the 3 groups at all time points and did not change during the study drug infusions. CONCLUSIONS: Abciximab does not decrease prothrombin activation and thrombin generation in patients with acute coronary syndromes without ST elevation not undergoing interventional procedures.

Effect of abciximab on prothrombin activation and thrombin generation in patients with acute myocardial infarction also receiving reteplase.

Fibrinolysis in acute myocardial infarction activates blood coagulation and may favor reocclusion or ischemic complications. The aim of the GUSTO V Italian Hematologic Substudy was to compare the effects of full-dose reteplase on coagulation activation markers with those of half-dose reteplase combined with full-dose abciximab, a platelet glycoprotein IIb/IIIa receptor antagonist, during the early phase after acute myocardial infarction.

The redefinition of acute myocardial infarction.

In the year 2000 a consensus document of the Joint European Society of Cardiology/American College of Cardiology Committee proposed new diagnostic criteria for acute myocardial infarction (MI), emphasizing the role of more sensitive and specific serologic biomarkers of myocardial necrosis. Although several criticisms soon followed this redefinition of acute MI, it was expected that these new criteria would substantially impact the clinical management and prognosis of patients with coronary artery disease. Important consequences on the health care system and government policies were supposed as well. However, 4 years later a substantial proportion of patients with acute MI are still diagnosed according to the old World Health Organization criteria, irrespective of the results of biomarker assays. This finding indicates that the redefinition of acute MI is far from being universally adopted. Thus, the reasons that hampered a widespread diffusion of such criteria, mainly a mixture of technical, logistic and cultural points, and the main, still controversial issues are discussed and commented on.

Silent acute myocardial infarction following a wasp sting.

Hymenoptera sting can lead to an acute myocardial infarction by different pathogenetic mechanisms depending on the presence of preexistent coronary atherosclerosis, the development of shock or the therapeutic use of epinephrine. The case of a 67-year-old man with acute myocardial infarction with ST-segment elevation after a wasp sting treated with fibrinolysis and without significant coronary atherosclerosis is reported. Of particular interest in the present case report is the silent presentation and the absence of any pharmacological interference. It follows that in any case of hymenoptera envenomation a standard ECG is advisable even when a clearly defined allergic reaction is not present.

[Concomitant left atrial myxoma and atrial fibrillation in patients with peripheral embolism]. / Concomitanza di mixoma atriale sinistro e fibrillazione atriale in pazienti con embolia periferica.

In the present article, 2 cases of left atrial myxoma and peripheral embolism in patients with concomitant paroxysmal or permanent atrial fibrillation are reported. In both cases, the embolic event was considered to be related to atrial fibrillation and the diagnosis of atrial myxoma was established later on at echocardiography. In view of the above, transesophageal echocardiography should be always performed after an embolic event, even in patients with established atrial fibrillation.