Optimizing the production of the biosurfactant lichenysin and its application in biofilm control.

AIMS: Apply response surface methodology (RSM) to develop and optimize an economical medium for lichenysin production, which is a surfactant produced by Bacillus licheniformis and evaluate the application of lichenysin in the prevention and disruption of pathogenic micro-organism biofilm that creates health problems in the food industry and hospitals. RESULTS: An economical medium containing molasses was optimized to enhance lichenysin production by RSM. A production of 3·2 g l(-1) of lichenysin was achieved with an optimum medium containing 107·82 g l(-1) of molasses, 6·47 g l(-1) of NaNO3 and 9·7 g l(-1) of K2 HPO4 /KH2 PO4 , in which molasses and phosphate salts had a significant effect on biosurfactant production. Lichenysin was effectively applied in a surface pre-treatment to avoid microbial biofilm development of methicillin-resistant Staphylococcus aureus (MRSA) (68·73%) and Candida albicans (74·35%), with ED50 values of 8·3 and 17·2 µg ml(-1) respectively. It was also very efficient in a surface post-treatment to remove biofilms of MRSA (55·74%) and Yersinia enterocolitica (51·51%), with an ED50 of 2·79 and 4·09 µg ml(-1) respectively. CONCLUSIONS: Lichenysin was found to have notable anti-adhesion activity, being able to prevent and eliminate the biofilm formation by pathogenic strains associated with foodborne illness. This new medium resulted in a four-fold increase in production compared with the nonoptimized medium. SIGNIFICANCE AND IMPACT OF THE STUDY: Molasses can be regarded as a useful resource for biotechnological applications, such as the production of lichenysin. The use of agro-industrial substrates has an important role in the sustainable and competitive development of several industrial sectors, as well as in industrial residues management. Additionally, lichenysin is particularly effective in preventing biofilm formation by strains problematic for the food industry and in the hospital environment. Lichenysin also efficiently disrupts biofilm.

Improvement of the Pour Plate Method by Separate Sterilization of Agar and Other Medium Components and Reduction of the Agar Concentration.

Although the pour plate method is widely employed in microbiological quality control, it has certain drawbacks, including having to melt the culture medium before seeding. In this study, the preparation of the culture medium was modified by using a lower concentration of agar (10 g/L), which was separated from the nutrients during sterilization. The new protocol was assessed in media frequently used in microbiological quality control of food, cosmetics, and pharmaceutical products, with tryptic soy agar (TSA), Sabouraud 4% dextrose agar (SDA), and violet red bile glucose agar (VRBG). In comparison with the conventionally produced media, the modifications significantly improved the growth of Saccharomyces cerevisiae in SDA, Staphylococcus aureus, Salmonella enterica subsp. enterica serovar Typhimurium, and Candida albicans in TSA and Escherichia coli ATCC 8739 and ATCC 25922 and S. Typhimurium in VRBG. The modified VRBG was also more selective for Pseudomonas aeruginosa. Regarding physicochemical properties, a significantly lower pH was observed in TSA and VRBG and lower strength values in TSA. Sterilizing agar separately from the other components of the medium and reducing the agar concentration to 10 g/L can improve microorganism growth and enhance the selectivity of differential media in the pour plate method. These modifications could facilitate the automation of this culture technique. IMPORTANCE In the era of rapid microbiological methods, there is a need to improve long-established culture techniques. Drawbacks of the pour plate method include having to melt each medium separately before seeding. For this technique, we demonstrate that separating the agar from the other components of commonly used media during sterilization and reducing the agar concentration to 10 g/L can enhance microbial growth. The new protocol could have advantages in routine laboratory practice because less agar is required and the same molten agar suspension can be used to prepare different media. Moreover, these modifications could facilitate the automation of the pour plate method.

Manchester triage in acute pulmonary embolism: can it unmask the grand impersonator?

BACKGROUND: Acute pulmonary embolism (PE) is associated with high mortality risk. Early diagnosis is difficult because of non-specific clinical presentation and delay in imaging confirmation. Manchester Triage (MT) prioritises patients on the basis of illness severity and potentially recognises those with higher mortality risk. No studies of the role and impact of MT on rapid PE diagnosis and in-hospital mortality (IHM) have been carried out. OBJECTIVE: To assess the appropriateness of MT in this set of patients presenting acutely to the emergency department (ED), and to determine whether it assists in a rapid diagnosis, acts as a protective triage tool and affects short-term mortality. METHODS: Single-centre retrospective study of 176 consecutive patients with PE, assessed by MT in the ED between January 2006 and October 2010 (mean age 70.5±15.7 years, 38.6% men). The primary outcome measure was all-cause IHM. RESULTS: IHM was seen in 30 (17%) patients. More than half of the patients with PE (54%) were classified as target time for first medical observation (MOb) ≤10 min. 73.3% of IHM occurred in this group (p=0.020) with several increased markers of illness severity. MOb ≤10 min was not associated with faster PE imaging confirmation. The average door-to-diagnosis time (PEDx) was 26.8±36.8 h and PEDx >17.0 h was associated with higher IHM (p=0.017). On multivariate analysis, thrombolysis and MOb ≤10 min were included in an IHM predictor model. CONCLUSION: MT has high sensitivity in identifying patients with PE at risk. Those patients assigned as MOb ≤10 min have increased markers of illness severity and higher IHM. MT acts as a protective system in this challenging set and should be used as a patient's first assessment, aiding the emergency medical team to recognise those in need of urgent assessment and treatment.

Improvement of Mueller-Kauffman Tetrathionate-Novobiocin (MKTTn) enrichment medium for the detection of Salmonella enterica by the addition of ex situ-generated tetrathionate.

The detection of Salmonella in food is based on the use of a selective enrichment broth such as Muller-Kauffman Tetrathionate-Novobiocin (MKTTn), in which tetrathionate plays a key role by providing Salmonella with a growth advantage. As sodium tetrathionate is unstable, it is generated in situ by the addition of iodine (Lugol's solution) before seeding. This step is cumbersome as the solution is easily spilled, compromising the performance of the medium and hindering the work of technicians. The aim of this study was to optimize MKTTn broth by generating tetrathionate ex situ through an external reaction between iodine and thiosulphate followed by lyophilization. Quality control procedures were performed to compare the modified and original media, testing pure productivity (enrichment with 50-120 CFU of Salmonella Thyphimurium ATCC 14028 and Salmonella Enteritidis ATCC 13076 and plating on Xylose Lysine Deoxycholate agar, XLD), mixed productivity (50-120 CFU of Salmonella strains and Pseudomonas aeruginosa and Escherichia coli at ≥104 CFU and XLD plating) and selectivity (≥104 CFU of P. aeruginosa and Enterococcus faecalis and plating on Tryptone Casein Soy agar, TSA). The modified MKTTn medium (S/L) performed comparably with the original medium in terms of growth of both Salmonella strains (>300 colonies in XLD), alone or with P. aeruginosa and E. coli. Quantitative assays showed no statistically significant differences in the number of colonies grown on XLD after 10-5 dilution (p = 0.7015 with S. Thyphimurium ATCC 14028 and p = 0.2387 with S. Enteritidis ATCC 13076; ANOVA test). MKTTn medium (S/L) was also selective against E. coli (≤100 colonies) and E. faecalis (<10 colonies). These results suggest that adding tetrathionate as a lyophilisate (S/L) is a feasible alternative to the use of Lugol's solution for the preparation of MKTTn enrichment broth and does not affect the properties of the medium.

Myocardial infarction with anomalous coronary anatomy.

Congenital coronary anomalies are rare but present a diagnostic challenge as detailed study of the coronary anatomy is required for their detection and accurate characterization. The authors present the case of a 71-year-old man with a previous history of angina, who had undergone cardiac catheterization several years ago, which was described as normal. He was admitted to our center with an acute myocardial infarction, three years after symptom onset; cardiac catheterization was repeated and revealed a subocclusive lesion located in a circumflex artery with an anomalous origin. We highlight the diagnostic difficulties encountered in this particular case, as the culprit artery was not identified in the first coronary angiography. Closer analysis of the images and the patient's clinical course helped identify the missing vessel, a dominant circumflex artery with an anomalous origin, and the atherosclerotic lesion responsible for the events.

Left ventricular noncompaction: an unusual cause of ventricular ectopic beats.

Isolated ventricular ectopic beats (VEB) are a frequent finding in clinical practice. Determining their etiology and risk stratification strategies requires exclusion of non-cardiac causes and structural heart disease. However, with advances in imaging techniques, molecular biology and electrophysiology, the concept of structural heart disease has changed, and it is important to consider the benefits of using these techniques in cases that have not been entirely clarified. The authors describe the case of a patient with frequent isolated VEB, with a find diagnosis of isolated noncompaction of the lefts ventricle following cardiac magnetic resonance imaging. They present an uncommon cause of VEB, which has raised questions regarding its real prevalence. Better diagnostic accuracy is expected with the use of new imaging techniques.

A rare histiocytosis with severe cardiac involvement: Erdheim-Chester disease.

The term histiocytosis covers various disorders that lead to primary proliferation, infiltration and accumulation of cells of the mononuclear-phagocytic system within the affected tissues. Its pathophysiology is still unclear and the clinical course variable, which explains the lack of specific treatment and the need for a high level of suspicion to arrive at the diagnosis. The authors present the case of a patient with a complex cardiological clinical history, recently referred for surgical treatment of severe mitral insufficiency. Severe thickening of both atrial walls made it impossible to proceed with the intervention. After a complex etiological evaluation, a diagnosis of Erdheim-Chester disease was made. This is a rare, non-Langerhans cell histiocytosis and, to our knowledge, this represents the first case reported in Portugal. The authors also review the literature, particularly of the few cases with cardiac involvement.

Viral myocarditis--new advances.

The role of viruses in cardiovascular disease has been increasingly recognized in recent years. They are now thought to be the main agent in acute myocarditis and inflammatory cardiomyopathy in the western world. We describe new perspectives on the part viral agents play in heart disease, from molecular mechanisms to recently available diagnostic and therapeutic options. We present a case of post-viral dilated cardiomyopathy in a 29-year-old woman in order to illustrate the severe damage that a viral infection can cause and the different therapeutic options that may be available in the near future.

Topological bound states in interacting Su-Schrieffer-Heeger rings.

We study two-particle states in a Su-Schrieffer-Heeger (SSH) chain with periodic boundary conditions and nearest-neighbor (NN) interactions. The system is mapped into a problem of a single particle in a two-dimensional (2D) SSH lattice with potential walls along specific edges. The 2D SSH model has a trivial Chern number but a non-trivial Zak's phase, the one-dimensional (1D) topological invariant, along specific directions of the lattice, which allow for the presence of topological edge states. Using center-of-mass and relative coordinates, we calculate the energy spectrum of these two-body states for strong interactions and find that, aside from the expected appearance of doublon bands, two extra in-gap bands are present. These are identified as bands of topological states localized at the edges of the internal coordinate, the relative distance between the two particles. As such, the topological states reported here are intrinsically many-body in what concerns their real space manifestation, having no counterpart in single-particle states derived from effective models. Finally, we compare the effect of Hubbard interactions with that of NN interactions to show how the presence of the topological bound states is specific to the latter case.

Acute myocardial infarction in the puerperium. A case report.

Acute myocardial infarction is a rare event in the puerperium that can have life-threatening consequences if not diagnosed early. Spontaneous coronary artery dissection is the most frequent causative mechanism in the period immediately after labor. This article reports the case of a 38-year-old woman with acute myocardial infarction due to spontaneous coronary artery dissection on the 7th day after delivery. The authors review this entity and also discuss the prognosis and future management of this patient.

Viability qPCR, a new tool for Legionella risk management.

BACKGROUND: Viability quantitative Polymerase Chain Reaction (v-qPCR) is a recent analytical approach for only detecting live microorganisms by DNA amplification-based methods This approach is based on the use of a reagent that irreversibly fixes dead cells DNA. In this study, we evaluate the utility of v-qPCR versus culture method for Legionellosis risk management. METHODS: The present study was performed using 116 real samples. Water samples were simultaneously analysed by culture, v-qPCR and qPCR methods. Results were compared by means of a non-parametric test. RESULTS: In 11.6% of samples using both methods (culture method and v-qPCR) results were positive, in 50.0% of samples both methods gave rise to negative results. As expected, equivalence between methods was not observed in all cases, as in 32.1% of samples positive results were obtained by v-qPCR and all of them gave rise to negative results by culture. Only in 6.3% of samples, with very low Legionella levels, was culture positive and v-qPCR negative. In 3.5% of samples, overgrowth of other bacteria did not allow performing the culture. When comparing both methods, significant differences between culture and v-qPCR were in the samples belonging to the cooling towers-evaporative condensers group. The v-qPCR method detected greater presence and obtained higher concentrations of Legionella spp. (p<0.001). Otherwise, no significant differences between methods were found in the rest of the groups. CONCLUSIONS: The v-qPCR method can be used as a quick tool to evaluate Legionellosis risk, especially in cooling towers-evaporative condensers, where this technique can detect higher levels than culture. The combined interpretation of PCR results along with the ratio of live cells is proposed as a tool for understanding the sample context and estimating the Legionellosis risk potential according to 4 levels of hierarchy.

Amino acid­based surfactants: New antimicrobial agents.

The rapid increase of drug resistant bacteria makes necessary the development of new antimicrobial agents. Synthetic amino acid-based surfactants constitute a promising alternative to conventional antimicrobial compounds given that they can be prepared from renewable raw materials. In this review, we discuss the structural features that promote antimicrobial activity of amino acid-based surfactants. Monocatenary, dicatenary and gemini surfactants that contain different amino acids on the polar head and show activity against bacteria are revised. The synthesis and basic physico-chemical properties have also been included.

Personal computer software evaluation in interactive generation of pig liver three-dimensional anatomical images.

The efficiency of software for a personal computer in the interactive generation of three-dimensional (3D) images from computer tomography was studied in six pig livers after hepatic resection and catheterization of the hepatic and portal veins. After perfusion the livers were submitted to computed tomography angiography, volumetric measurement by water displacement, and production of an acrylic model of the veins by the injection and corrosion method, by which the lengths of the hepatic and portal veins were measured. From the angiogram, the software generated a 3D image that allowed measurement of the vein lengths. The identified branches of the hepatic and portal veins were correlated with the hepatic sectors and segments, respectively. The virtual measures from the 3D images were compared with the real measures. There were no significant differences between the topography and the vessel length. The mean difference between the volumes calculated from software and those measured by water displacement corresponded to 1.2%, and between the vessel lengths, 0.2%. In conclusion, the software for personal computer (named LIVER3D) is efficient, allowing interactive inspection of 3D images. All virtual measurements of liver vessel length and partial/total liver volume were similar to the actual ones.

Hypoglycemic Effect of the Methanol flower Extract of Piper Claussenianum and the Major Constituent 2',6'-dihydroxy-4'-methoxychalcone in Streptozotocin Diabetic Rats.

Piper claussenianum inflorescences crude methanol extract was tested for hypoglycemic effect in streptozotocin-induced diabetic rats. The blood glucose levels of rats treated with methanol extract were reduced from 318.4±28.1 mg/dl before treatment to 174.2±38.3 mg/dl after 12 days of treatment (P<0.05). Phytochemical studies were carried out on inflorescences methanol crude extract in order to investigate the possible metabolites responsible for the pharmacological properties of the extract. After chromatographic procedures, three flavonoids were isolated and characterized. The major compound 2',6'-dihydroxy-4'-methoxychalcone was also tested. Rats that received the chalcone content also displayed a reduction in blood glucose levels from 277.4±7.7 mg/dl before treatment to 158.8±9.2 mg/dl after 12 days of treatment (P<0.05). The results suggest this chalcone is one of the metabolite responsible for the blood glucose levels reduction in rats with streptozotocin-induced diabetes. The inflorescence crude extract of P. claussenianum was found to be composed mainly by flavonoids and may be a potential natural source of compounds with hypoglycemic properties.

Sector field inductively coupled plasma mass spectrometry, another tool for plutonium isotopes and plutonium isotope ratios determination in environmental matrices.

The transfer of radio nuclides into the different compartments of the environment are widely studied and leads to the elaboration of transfer models in order to evaluate potential impact onto the environment and humans. Accurate experimental data are needed to validate these models for all types of matrices (air, water, sediments, soils, biota and food...). Among these radionuclides, 238Pu, 239Pu, 240Pu and 241Pu, are often mentioned. They have been released into the environment by nuclear weapon tests, nuclear facilities, reactors or satellite accidents. These different sources have different 240Pu/239Pu ratios and therefore this ratio is used to provide information on the source of contamination into the environment. The most conventional analytical tools used for plutonium isotope determination are liquid scintillation and alpha spectrometry, and thermal ionisation mass spectrometry (TIMS) is still considered as the primary method for determination of plutonium isotope ratios. During the last decade, mass spectrometers equipped with plasma ion sources and sector field analysers were developed and can offer now another alternative method for the accurate determination of isotope content and ratios of long-lived radionuclides in environmental samples. This paper presents and discusses the results obtained for 239Pu, 240Pu and 241Pu content and isotope ratios by sector field ICP-MS in different environmental matrices.

[Myocardial infarct in a young man with normal coronary vessels: apropos of a clinical case treated with streptokinase]. / Enfarte do miocárdio em jovem com coronárias normais: a propósito de um caso clínico tratado com estreptoquinase.

The authors report a case of a 31 year old young man who suffered acute myocardial infarction and was subjected to early treatment with streptokinase. The immediate follow-up showed a complete recanalization of the infarct-related vessel, without any identifiable obstructive lesion on coronary arteriography. Related to this angiographic finding, common in myocardial infarction in the young adult, the authors debate the implicated mechanisms, focusing essentially in the relation endothelium-platelets-vasomotricity. The issue of cigarette smoking as a risk factor and its possible pathogenic implication, even in the absence of atherosclerotic plaque, is also approached.

[Traumatic aortic valve insufficiency]. / Insuficiência valvular aórtica traumática.

The traumatic aortic valvular insufficiency (TAVI), through less frequent after a non-penetrating thoracic traumatism, is a serious entity with a very reserved prognosis. So it must be suspected in every patients with signs or symptoms of de novo heart failure post-traumatism. The transthoracic echocardiography and eventually transesophageal echocardiography have a fundamental role in the confirmation of the diagnosis. The clinical picture of traumatic aortic regurgitation is quickly evolutionary and the non efficacy of medical therapy has placed the valvular substitution surgery as the best succeeded treatment. With the advent of the aortic valve repairing surgery some TAVI cases has been submitted to this procedure. Nevertheless, the development of residual aortic regurgitation in these situations, usually requiring later valvular replacement surgery, make the aortic valvuloplasty a controversial surgical technique. The AA describe a recent clinical case of aortic regurgitation after a non-penetrant thoracic traumatism, discussing the aspects connected with physiopathology, diagnosis and therapy. The singularity of this case was based on the fact that the initial clinical diagnosis had been prejudiced by the context of a polytraumatism and there had been a time free of symptoms between the traumatism and the beginning of the symptomatology of left ventricular failure. Even though the identification of the problem allowed an intensive treatment of this serious situation that ended with the replacement of the aortic valve by mechanical aortic prosthesis, with the patient's total recovery.

[Adjuvant therapy with a glycoprotein IIb-IIa inhibitor (abciximab) in coronary angioplasties with a high thrombotic risk]. / Terapêutica adjuvante com inibidor da glicoproteína IIb-IIIa (abciximab) em angioplastias coronárias com elevado risco trombótico.

INTRODUCTION: We retrospectively studied our experience with adjunctive therapy with glycoprotein IIb-IIIa inhibitor (abciximab) on patients with a high risk of thrombotic complications during coronary angioplasty (PTCA). PATIENTS AND METHODS: From September 1996 to November 1997, we performed PTCA in 210 patients, and abciximab was given to 38 (18%) of them. The interventions were urgent (primary PTCA in acute myocardial infarction) in 55% of the cases. The mean age of patients was 68.6 +/- 12 years and 71% were male. The reasons for coronary intervention were: acute myocardial infarction in 21 patients (55.3%), unstable angina in 9 (23.7%) and stable angina in 8 (21%). Coronary stents were implanted in 13 patients (34%) and an intra aortic balloon pump was used in 4 (11%). The reasons for using abciximab were: thrombus containing lesion: 22 (57.9%); other type B2/C lesion characteristics: 6 (15.9%); acute closure post balloon PTCA: 9 (23.7%), sub-acute stent thrombosis: 1 (2.6%). Oral acetilsalicilic acid and intravenous heparin were given to all patients at the beginning of the intervention. The mean APTT was 124 +/- 32 seconds at the end of the procedure. RESULTS: The arterial sheaths (8 French) were removed six hours after procedure, according to the normalisation of APTT values. Angiographic success in this group of patients was 100%. One patient died during hospitalisation due to left ventricular failure. There was no need for repeated angioplasty or coronary bypass grafting during hospital stay. The main complications related to the use of abciximab were: bleeding (requiring transfusion) in four patients 10.5%); severe thrombocytopenia (< 50,000 platelets/mm3): 1 (2.6%): cardiac tamponade (requiring pericardiocentesis): 1 (2.6%) and pseudo-aneurysm of femoral artery (requiring vascular surgery): 1 (2.6%). CONCLUSIONS: The use of abciximab as adjunctive therapy in this small group of patients undergoing coronary interventions with high risk of thrombotic complications is associated with high procedural success, but at the expense of high rates of bleeding complications. Therefore, special care must be applied during and after the procedure to enhance the safety of the patients treated with this drug.

[Primary tricuspid valve insufficiency. Report of 2 clinical cases]. / Insuficiência tricúspide primária. A propósito de dois casos clínicos.

Two case reports of primary tricuspid regurgitation are presented which diagnoses were made in mean adult life after a long period of few symptoms. The clinical outcome of the two cases was uneven in the sense that only one of them could be corrected with single surgical procedures. Despite relatively rare, this pathology could probably be turned more frequent with a complete and systematic echocardiographic approach. In connection with the reported cases, a review is made of the main etiologies and of some published reports.