Fermentation study for the production of hepatitis B virus pre-S2 antigen by the methylotrophic yeast Hansenula polymorpha.

Various physico-chemical parameters have been studied in order to improve the production of hepatitis B virus pre-S2 antigen (middle surface antigen) by the methylotrophic yeast Hansenula polymorpha. Antigen production was done in two steps: first, production of cells on glycerol (Phase 1), followed by induction of antigen expression with methanol (Phase 2). Dense cultures of H. polymorpha, equivalent to 35-40 g/l (dry weight), were readily obtained in small fermenters using minimal medium containing glycerol as carbon source. Antigen expression in this minimal medium, after induction with methanol, was however, low and never exceeded 1.6 mg/l of culture. Antigen production was greatly enhanced by adding complex organic nitrogen sources along with methanol at induction time; yeast extract was the best of all the sources tested. In shake flasks, antigen production was proportional to yeast extract concentration up to 7% (w/v) yeast extract, it became clear the the nutritional conditions for good antigen expression were different from those for good biomass production. The effects of yeast extract were reproduced in small fermenters: antigen levels reached 8-9 mg/l in medium containing 6% (w/v) yeast extract during induction with methanol. The mechanisms of yeast extract's effects are still unknown but are probably nutritional. The recombinant H. polymorpha strain produced both periplasmic and intracellular antigen. The periplasmic antigen was shown to be present as 20-22-nm particles and was therefore immunogenic. Immunoblotting indicated that part of the pre-S2 antigen was present as a 24-kDa degradation product. These studies have led to a 140-fold increase in volumetric productivity of antigen and to a 4.6-fold increase in specific production

Correlated Microscopic Observations of Arterial Responses to Intravascular Stenting

Percutaneous catheter implantation of intravascular stent prostheses has emerged as a novel clinical adjunct to balloon angioplasty in the treatment of obstructive atherosclerotic vascular disease. We have examined the cellular and subcellular responses to stenting in the coronary arteries of the dog and pig (both normal and atherosclerotic), and in the iliac arteries and aorta of the atherosclerotic rabbit, using scanning electron, transmission electron, and light microscopies. Stenting in these models resulted in a thrombotic reaction ranging from mild to severe, depending on species and antithrombotic therapy. Subsequent organization of thrombotic material with hyperplasia of smooth muscle and inflammatory cells, luminal recovering with endothelial or pseudoendothelial cells, and atrophy of the tunica media led to incorporation of the prosthesis into the arterial wall. Endothelial or pseudoendothelial cells were observed adherent to the prosthesis as early as one day after placement, and regeneration of a confluent periluminal cell layer occurred within 2 to 4 weeks. Persistent ultrastructural abnormalities of the periluminal cell layer were seen as late as 2 years after stenting, but the intimal hyperplastic response appeared limited

Raman micro-spectroscopy as a tool to measure the absorption coefficient and the erosion rate of hydrogenated amorphous carbon films heat-treated under hydrogen bombardment

We present a fast and simple way to determine the erosion rate and absorption coefficient of hydrogenated amorphous carbon films exposed to a hydrogen atomic source based on ex-situ Raman micro-spectroscopy. Results are compared to ellipsometry measurement. The method is applied to films eroded at different temperatures. A maximum of the erosion rate is found at ~ 450 {\degree}C in agreement with previous results. This technique is suitable for future quantitative studies on the erosion of thin carbonaceous films, especially of interest for plasma wall interactions occurring in thermonuclear fusion devices

"Assessment of effectiveness and security in high pressure postdilatation of bioresorbable vascular scaffolds during percutaneous coronary intervention. Study in a contemporary, non-selected cohort of Spanish patients"

OBJECTIVES: To determine security and benefits of high pressure postdilatation (HPP) of bioresorbable vascular scaffolds (BVS) in percutaneous coronary intervention (PCI) of complex lesions whatever its indication is. BACKGROUND: Acute scaffold disruption has been proposed as the main limitation of BVS when they are overexpanded. However, clinical implications of this disarray are not yet clear and more evidence is needed. METHODS: A total of 25 BVS were deployed during PCI of 14 complex lesions after mandatory predilatation. In all cases HPP was performed with NC balloon in a 1:1 relation to the artery. After that, optical coherence tomography (OCT) analyses were performed. RESULTS: Mean and maximal postdilatation pressure were 17±3.80 and 20 atmospheres (atm) respectively. Postdilatation balloon/scaffold diameter ratio was 1.01. A total of 39,590 struts were analyzed. Mean, minimal and maximal scaffold diameter were respectively: 3.09±0.34mm, 2.88±0.31mm and 3.31±0.40mm. Mean eccentricity index was 0.13±0.05. ISA percentage was 1.42% with a total of 564 malapposed struts. 89 struts were identified as disrupted, which represents a percentage of disrupted struts of 0.22%. At 30days, none of our patients died, suffered from stroke, stent thrombosis or needed target lesion revascularization (TLR). CONCLUSIONS: NC balloon HPP of BVS at more than 17atm (up to 20atm) is safe during PCI and allows to achieve better angiographic and clinical results

Raman study of CFC tiles extracted from the toroidal pump limiter of Tore Supra

International audienceThe structure of six tiles extracted from the erosion and deposition zones (thin and thick deposition) of the Tore Supra toroidal pump limiter (TPL) have been analysed in the framework of the DITS campaign using micro-Raman spectroscopy. This post-mortem analysis gives information on both carbon structure and D content. We have found that the carbon structure is most often similar to that of plasma-deposited hard amorphous carbon layers. The role of the surface temperature during the discharge in the D content is investigated: in all locations where the temperature does not reach more than 500°C the D content seems to be roughly uniform with D/D+C ≈ 20%

In-hospital outcomes of mechanical complications in acute myocardial infarction: Analysis from a nationwide Spanish database

Background: Mechanical complications represent an important cause of mortality in myocardial infarction (MI) patients. This is a nationwide study performed to evaluate possible changes in epidemiology or prognosis of these complications with current available strategies.Methods: Information was obtained from the minimum basis data set of the Spanish National Health System, including all hospitalizations for acute myocardial infarction (AMI) from 2010 to 2015. Risk-standardized in-hospital mortality ratio was calculated using multilevel risk adjustment models.Results: A total of 241,760 AMI episodes were analyzed, MI mechanical complications were observed in 842 patients: cardiac tamponade in 587, ventricular septal rupture in 126, and mitral regurgitation due to papillary muscle or chordae tendineae rupture in 155 (there was more than one complication in 21 patients). In-hospital mortality was 59.5%. On multivariate adjustment, variables with significant impact on in-hospital mortality were: age (OR 1.06; 95% CI 1.04-1.07; p < 0.001), ST-segment elevation AMI (OR 2.91; 95% CI 1.88-4.5; p < 0.001), cardiogenic shock (OR 2.35; 95% CI 1.66-3.32; p < 0.001), cardio-respiratory failure (OR 3.48; 95% CI 2.37-5.09; p < 0.001), and chronic obstructive pulmonary disease (OR 1.85; 95% CI 1.07-3.20; p < 0.001). No significant trends in risk-adjusted in-hospital mortality were detected (IRR 0.997; p = 0.109). Cardiac intensive care unit availability and more experience with mechanical complications management were associated with lower adjusted mortality rates (56.7 ± 5.8 vs. 60.1 ± 4.5; and 57 ± 6.1 vs. 59.9 ± 5.6, respectively; p < 0.001).Conclusions: Mechanical complications occur in 3.5 per thousand AMI, with no significant trends to better survival over the past few years. Advanced age, cardiogenic shock and cardio-respiratory failure are the most important risk factors for in-hospital mortality. Higher experience and specialized cardiac intensive care units are associated with better outcomes